Exhibit 10.1

                            STOCK PURCHASE AGREEMENT

                                  BY AND AMONG

                               WILLIAM G. KELLER,

                                THOMAS A. KELLER

                                       AND

                           NATIONAL DENTEX CORPORATION



                                TABLE OF CONTENTS


                                                                           
1. Purchase and Sale of the Shares.........................................    1

2. Consideration...........................................................    1
   (a)  Purchase Price.....................................................    1
   (b)  Closing Balance Sheet..............................................    2

3. Closing.................................................................    3

4. Representations and Warranties of the Stockholders......................    3
   (a)  Organization.......................................................    3
   (b)  Authority and Binding Effect.......................................    3
   (c)  Non-contravention..................................................    4
   (d)  Compliance with Laws...............................................    4
   (e)  Governmental Approval; Permits.....................................    5
   (f)  Capitalization.....................................................    5
   (g)  Title to Shares....................................................    6
   (h)  Financial Statements...............................................    6
   (i)  Absence of Certain Changes or Events...............................    6
   (j)  Assumptions or Guaranties of Indebtedness of Other Persons.........    9
   (k)  Inventory and Accounts Receivable..................................    9
   (l)  Contracts..........................................................    9
   (m)  Assets and Properties..............................................   10
   (n)  Litigation; and Claims.............................................   10
   (o)  Taxes..............................................................   10
   (p)  No Change in Business..............................................   13
   (q)  Real Estate........................................................   13
   (r)  Environmental Matters..............................................   14
   (s)  Insurance..........................................................   14
   (t)  Employees; and Employee Benefit Plans..............................   15
   (u)  Labor Matters......................................................   16
   (v)  Product Liability and Recalls......................................   17
   (w)  Transactions with Affiliates.......................................   18
   (x)  Books and Records..................................................   18
   (y)  Brokerage..........................................................   18
   (z)  Lines of Credit....................................................   18
   (aa) Disclosure.........................................................   18



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5. Buyer's Representations and Warranties..................................   18
   (a)  Organization and Authority.........................................   19
   (b)  Binding Effect.....................................................   19
   (c)  Non-Contravention..................................................   19
   (d)  Litigation.........................................................   19
   (e)  Disclosure.........................................................   19
   (f)  Brokerage..........................................................   19

6. Conditions to Buyer's Obligations.......................................   19
   (a)  Representations and Warranties.....................................   20
   (b)  No Adverse Change..................................................   20
   (c)  Compliance with Agreement..........................................   20
   (d)  Proceedings and Instruments Satisfactory...........................   20
   (e)  No Litigation......................................................   20
   (f)  Transfer of 124 Larkin Williams, LLC Assets........................   20
   (g)  Employment Agreements..............................................   20
   (h)  Non-Competition Agreements.........................................   21
   (i)  Deliveries.........................................................   21

7. Conditions to the Stockholders' Obligations.............................   22
   (a)  Representations and Warranties.....................................   22
   (b)  Compliance with Agreement..........................................   22
   (c)  Proceedings and Instruments Satisfactory...........................   22
   (d)  No Litigation......................................................   23
   (e)  Employment Agreements..............................................   23
   (f)  Non-Competition Agreements.........................................   23
   (g)  Deliveries.........................................................   23

8. Survival of Representations.............................................   24
   (a)  Survival of Representations........................................   24
   (b)  Statements as Representations......................................   24

9. Indemnification by the Stockholders.....................................   24
   (a)  Indemnity..........................................................   24
   (b)  Payment of Losses..................................................   25
   (c)  Third-Party Claims.................................................   25
   (d)  Cumulative Remedies................................................   26

10. Indemnification by Buyer...............................................   26
   (a)  Indemnity..........................................................   26
   (b)  Payment of Losses..................................................   26



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   (c)  Third-Party Claims.................................................   26
   (d)  Cumulative Remedies................................................   27

11. Press Releases.........................................................   27

12. Covenants and Agreements of the Stockholders and Buyer.................   27
   (a)  Tax Filing.........................................................   27
   (b)  Tax Proceedings....................................................   27

13. Miscellaneous Provisions...............................................   28
   (a)  Expenses...........................................................   28
   (b)  Assignability; Binding Effect......................................   28
   (c)  Notice.............................................................   28
   (d)  Governing Law......................................................   29
   (e)  Consent to Jurisdiction............................................   29
   (f)  Entire Agreement; Severability.....................................   29
   (g)  No Waiver..........................................................   29
   (h)  Arbitration........................................................   29
   (i)  Further Assurances.................................................   30
   (j)  Counterparts.......................................................   30



                                       iii


                            STOCK PURCHASE AGREEMENT

     THIS STOCK PURCHASE AGREEMENT (this "Agreement") is made as of the 5th day
of October 2006, by and among WILLIAM G. KELLER AND THOMAS A. KELLER (each a
"Stockholder", and together, the "Stockholders") and NATIONAL DENTEX
CORPORATION, a Massachusetts corporation ("Buyer").

                                   WITNESSETH:

     WHEREAS, Keller Group, Incorporated, a Missouri corporation (the
"Company"), operates a dental laboratory business at 160 Larkin Williams
Industrial Court, Fenton, MO 63026 and at 1700 Cargo Court, Louisville, KY
40299, and a sales office at 1420 Northwest Vivion Road, Suite 108, Kansas City,
MO 64118-4555;

     WHEREAS, the Stockholders collectively own of record all of the issued and
outstanding Shares (as defined in Section 4(f)) of the Common Stock (as defined
in Section 4(f)) of the Company, which Shares represent all of the issued and
outstanding capital stock of the Company; and

     WHEREAS, the Stockholders desire to sell to Buyer, and Buyer desires to
purchase from the Stockholders, the Shares upon the terms and conditions
hereinafter set forth.

     NOW, THEREFORE, in consideration of the agreements and covenants contained
herein, and for other good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, the parties hereby agree as
follows:

     1. Purchase and Sale of the Shares. Subject to the terms and conditions of
this Agreement and in reliance upon the representations and warranties of the
parties set forth herein, the Stockholders shall sell to Buyer, and Buyer shall
purchase from the Stockholders, the Shares on the Closing Date (as defined in
Section 3), for the consideration set forth in Section 2.

     2. Consideration.

          (a) Purchase Price. The purchase price for the Shares (the "Purchase
     Price") shall be calculated and payable as follows:

               (i) At the Closing, Buyer shall pay Nineteen Million One Hundred
          Twenty-five Thousand Dollars ($19,125,000) by wire transfer (the
          "Closing Payment") to the Stockholders, which amount shall be
          allocated Fifty Percent (50%) to each Stockholder; and

               (ii) Buyer shall pay each Stockholder an amount (the "Deferred
          Payment"), subject to adjustment in accordance with Section 2(b),
          equal to forty-one


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          percent (41%) of the ordinary business income of such Stockholder from
          the Company as set forth in the Schedule K-1 (as hereinafter defined),
          line 1 less line 11 of such Schedule K-1 minus the $105,000
          distributed by the Company during the current fiscal year of the
          Company to such Stockholder. The Deferred Payment shall be paid by
          Buyer to each Stockholder within thirty (30) days after the filing by
          the Company with the Internal Revenue Service of its final Form 1120S
          for the current fiscal year of the Company. The "Schedule K-1" means,
          with respect to each Stockholder, the final form K-1 issued by the
          Company to each Stockholder setting forth the ordinary income of such
          Stockholder from the Company for the current fiscal year of the
          Company.

          (b) Closing Balance Sheet.

               (i) On or prior to the Closing Date, the Stockholders and Buyer
          shall jointly prepare a pro forma consolidated balance sheet of the
          Company and its subsidiaries as of the Effective Date (as defined in
          Section 3) (the "Pro Forma Closing Balance Sheet"), in accordance with
          generally accepted accounting principles ("GAAP") consistently applied
          and compiled in accordance with the Standards for Accounting and
          Review Services issued by the American Institute of Certified Public
          Accountants (the "Standards").

               (ii) Within sixty (60) days after the Effective Date, Buyer with
          the assistance of the Stockholders shall prepare a consolidated
          balance sheet of the Company and its subsidiaries as of the Effective
          Date (the "Closing Balance Sheet"), in accordance with GAAP and
          compiled in accordance with the Standards, Buyer shall, by notice,
          provide each Stockholder with the Closing Balance Sheet. Each
          Stockholder shall have a period of twenty (20) days after the notice
          from the Buyer within which to give notice to Buyer that he either (i)
          accepts the Closing Balance Sheet or (ii) disputes the Closing Balance
          Sheet, including a statement in reasonable detail of the disputed
          items. If a Stockholder fails to give notice to Buyer within such
          twenty (20) day period, he shall be deemed to have accepted the
          Closing Balance Sheet. If a Stockholder gives Buyer notice that he
          disputes the Closing Balance Sheet, then Buyer and the Stockholder(s)
          shall meet as soon as reasonably possible (but in any event within
          twenty (20) days after notice by the Stockholder(s)) and attempt, in
          good faith, to resolve the dispute. If the parties are unable to agree
          upon the Closing Balance Sheet, or any portion thereof, within fifteen
          (15) days after the parties have commenced resolution of the dispute,
          then the matter shall be submitted for resolution to a mutually
          agreeable certified public accounting firm (the "Independent
          Accountants"), whose determination shall be final and binding upon the
          parties, and whose fees shall be borne equally by the Stockholders and
          Buyer except, however, that if the Independent Accountants determine
          that the Closing Balance Sheet proposed by Buyer was correct in its
          entirety, then the Stockholders shall be solely responsible for the
          fees of the Independent Accountants; and if the Independent
          Accountants determine that the dispute in the Closing Balance Sheet


                                        2



          should be resolved in favor of the Stockholders in its entirety, then
          Buyer shall be solely responsible for the fees of the Independent
          Accountants.

     3. Closing. The closing of the purchase and sale of the Shares (the
"Closing") shall take place on October 5, 2006 (the "Closing Date") and shall be
deemed to have been effective as of opening of business on October 2, 2006 (the
"Effective Date").

     4. Representations and Warranties of the Stockholders. The Stockholders,
jointly and severally, represent and warrant to Buyer as follows:

          (a) Organization. Set forth on Schedule 4(a) hereto is the name, state
     of organization and jurisdictions of foreign qualifications of the Company
     and of each corporation, limited liability company or other entity in which
     the Company owns, directly or indirectly, any equity interest (each a
     "Subsidiary" and together, the "Subsidiaries"). Schedule 4(a) also sets
     forth the Company's percentage ownership interest in each Subsidiary. The
     Company is a corporation, duly organized, validly existing and in good
     standing under the laws of the State of Missouri. Each Subsidiary is the
     type of entity set forth on Schedule 4(a), duly organized, validly existing
     and in good standing under the laws of its state of organization set forth
     on Schedule 4(a). The Company and each Subsidiary has all requisite
     corporate power and authority to own its property and to carry on its
     business as presently conducted. The Company and each Subsidiary is duly
     qualified as a foreign corporation to do business and is in good standing
     in each jurisdiction where the nature of the business conducted by the
     Company or such Subsidiary or its assets located therein requires such
     qualification, except where failure to do so would not have a Material
     Adverse Effect (meaning any material adverse change, event, circumstance or
     development with respect to, or material adverse effect on, the business,
     assets or properties, liabilities, capitalization, condition (financial or
     other), prospects or results of operations of the Company and its
     Subsidiaries, taken as a whole. For the avoidance of doubt, the parties
     agree that the terms "material", "materially" or "materiality" as used in
     this Agreement with an initial lower case "m" shall have their respective
     customary and ordinary meanings, without regard to this meaning). The
     Company and each Subsidiary is in good standing in each of the foreign
     jurisdictions in which it is qualified as set forth on Schedule 4(a).

          (b) Authority and Binding Effect. Each Stockholder has full legal
     right, and complete and unrestricted power, authority and capacity to
     execute and deliver this Agreement and the other agreements, documents and
     instruments to be executed and delivered by him pursuant hereto, to
     consummate the transaction contemplated hereby and perform his obligations
     under this Agreement and the agreements executed and delivered by him
     pursuant hereto. This Agreement and all such other agreements, documents
     and instruments have been, or will be, duly executed and delivered by each
     Stockholder and constitute, or will constitute when executed and delivered,
     valid and binding obligations of each Stockholder, enforceable against him
     in accordance with their respective terms.


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          (c) Non-contravention. The execution and delivery by the Stockholders
     of this Agreement and all other agreements, documents and instruments to be
     executed in connection herewith, and the consummation of the transactions
     contemplated and compliance with the provisions contained herein and
     therein, do not, and will not, (i) conflict with or violate any of the
     provisions of the charter documents, by-laws or other organization
     documents of the Company or any Subsidiary, (ii) with or without the
     passage of time, constitute a violation of, a default (or an event that
     with notice or lapse of time or both would constitute a default) under,
     give rise to any right of termination, amendment, cancellation,
     acceleration or any other right under, conflict with, modify any
     obligations under, require any consent, approval, notice or other action
     under, or increase the liability of the Company under, any contract, lease,
     indenture, agreement, deed of trust, license, order, judgment or decree or
     other instrument to which the Company or any Subsidiary is a party or by
     which any of them is bound or to which any of the assets of the Company or
     any Subsidiary are subject, and does not, and will not, violate or
     constitute a default (or an event that with notice or lapse of time or both
     would become a default) under any statute, rule, regulation, order, or
     ordinance of any governmental, judicial or arbitrary body, (iii) result in
     the creation of any encumbrance, lien, mortgage, charge, claim, option,
     pledge, license, sublicense, security interest, assignment by way of
     security, call, proxy or similar restriction on the Shares or any assets or
     properties of the Company or any Subsidiary, or (iv) conflict with,
     contravene or violate any law, statute, ordinance, rule or regulation, or
     any order, writ, judgment, injunction, consent, decree, determination or
     award of any court or any governmental agency or authority, currently in
     effect relating to the Company or any Subsidiary or any of their properties
     or assets.

          (d) Compliance with Laws.

               (i) The Company and each Subsidiary is currently conducting, and
          has at all times conducted its business in compliance in all respects
          with (A) its charter documents, by-laws and other organizational
          documents and (B) all applicable Federal, state and local laws,
          statutes, rules, regulations, ordinances and orders, judicial or
          administrative judgments, decrees, orders, settlements, writs,
          injunctions or similar commands, except where the failure to do so
          would not have a Material Adverse Effect. Without limiting the
          generality of the foregoing, the Company and each Subsidiary currently
          conducts, and has at all times conducted, its business in compliance
          with all applicable Federal, state and local laws, statutes,
          regulations, ordinances and rules concerning the collection, use,
          storage and transmission of patient information, export controls,
          export and foreign exchange laws and the United States Foreign Corrupt
          Practices Act.

               (ii) Neither the Company nor any Subsidiary is in default with
          respect to any judgment, order, writ, injunction, decree, demand or
          assessment issued by any court or of any Federal, state, municipal or
          other governmental agency, authority, board, commission, bureau,
          instrumentality or department relating to any aspect of its business
          or assets.


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               (iii) Neither the Company nor any Subsidiary has been charged or,
          to the Stockholders' knowledge, threatened with, and is not under
          investigation with respect to, any violation of any provision of any
          Federal, state, municipal or other law or administrative rule or
          regulation relating to its business or assets.

               (iv) The Company and each Subsidiary currently is, and has at all
          times been, in compliance with all requirements of insurance carriers
          applicable to its business and assets.

          (e) Governmental Approval; Permits.

               (i) Except as set forth on Schedule 4(e), no consent, approval or
          authorization of, or registration, designation, declaration or filing
          with, any governmental agency or authority, whether domestic, foreign,
          Federal, state, municipal or other, on the part of the Company, any
          Subsidiary or either Stockholder, is required in connection with the
          execution and delivery by the Stockholders of this Agreement, or the
          other agreements, documents and instruments executed and delivered,
          and to be executed and delivered, and to be executed and delivered, by
          any Stockholder pursuant hereto and the consummation of the
          transactions provided for herein and therein.

               (ii) Set forth on Schedule 4(e) is a true, correct and complete
          list of all licenses and permits of the Company and the Subsidiaries
          (the "Licenses"), copies of which have been delivered by the
          Stockholders to Buyer. The Company and each Subsidiary has all
          licenses, permits and other governmental authorizations required for
          the conduct of its business or ownership of its assets, and the
          consummation of the transactions contemplated hereby, and is in
          compliance therewith. The Licenses are in full force and effect
          without default or notice of default and will not be impaired as a
          result of, and will remain in full force and effect after the
          consummation of the transactions contemplated hereby.

          (f) Capitalization. The authorized capital stock of the Company
     consists of 2,350 shares of capital stock, of which (i) 500 shares are
     voting common stock, $1.00 par value per share (the "Common Stock"), 200
     shares of which are issued and outstanding (the "Shares"), and (ii) 1,850
     are preferred stock, $100.00 par value per share, of which no shares are
     issued and outstanding. The shares of capital stock or other equity
     interests of the Company in each Subsidiary are owned by the Company as set
     forth on Schedule 4(a). No other shares of capital stock of the Company or
     any Subsidiary are issued, outstanding or reserved for issuance upon the
     exercise of outstanding options or other rights to purchase shares. All of
     the Shares and all equity interests of the Company in each Subsidiary have
     been duly authorized and validly issued, and are fully paid and
     non-assessable, and were not issued in violation of any preemptive or other
     similar rights and are not subject to preemptive or other similar rights.
     There are not authorized, issued or outstanding any commitments for the
     purchase or sale of, or any options, warrants or other rights to subscribe
     for or purchase, any shares of the capital stock or other securities or
     equity


                                       5



     interests of the Company or any Subsidiary, nor is the Company or any
     Subsidiary obligated in any other manner to issue shares of its capital
     stock or other securities, including securities convertible into or
     exchangeable for capital stock. Except as set forth on Schedule 4(f) there
     are no restrictions on the transfer of shares of the Company's capital
     stock or other equity interests, including the Shares, other than those
     imposed by relevant Federal and state securities laws. The transfer
     restrictions set forth on Schedule 4(f) have been duly waived by the
     Stockholders to permit the sale of the Shares to Buyer hereunder. The
     Shares have been offered and sold by the Company to the Stockholders in
     compliance with all Federal and state securities laws. The Stockholders
     have made available to Buyer true and correct copies of the charter and
     by-laws of the Company and each Subsidiary, each as in effect as of the
     date hereof. Except as set forth on Schedule 4(f), there are not any
     shareholder agreements, voting trusts, proxies or other similar agreements
     or understandings with respect to or concerning the capital stock of the
     Company or any Subsidiary. Neither the Company nor any Subsidiary has any
     outstanding stock appreciations rights, phantom stock or equivalents.

          (g) Title to Shares. Each Stockholder, for himself, severally and not
     jointly, represents and warrants that: (i) 100 Shares are owned of record
     and beneficially by such Stockholder and such Stockholder will transfer
     such Shares to Buyer on the Closing Date, free and clear of all liens,
     encumbrances, options or other rights of any nature; and (ii) there are not
     authorized, issued or outstanding any agreements, commitments or
     understandings for the purchase or sale of, or any options to purchase or
     other rights relating to his or her Shares which have not been duly and
     validly waived to permit the sale of such Shares to Buyer in accordance
     with this Agreement.

          (h) Financial Statements. The Stockholders have delivered to Buyer,
     and there is attached as Schedule 4(h), a copy of the audited annual
     consolidated financial statements of the Company and its Subsidiaries for
     the fiscal years ended December 31, 2003, 2004 and 2005 and internally
     prepared financial statements for the eight (8) months ended August 31,
     2006 (the "Financial Statements"). The Financial Statements are (i) true,
     correct and complete; (ii) fairly present the financial condition and
     results of operations of the Company as of the date thereof; (iii) were
     prepared in accordance with GAAP and the Standards and in a manner
     consistent with past practice; and (iv) were prepared in accordance with
     the books, records and accounts of the Company and its Subsidiaries, which
     books, records and accounts are correct and complete in all material
     respects. Except to the extent reflected or reserved against in the
     Financial Statements, the Company and its Subsidiaries as of the date
     thereof did not have and will not have any liabilities or obligations of
     any nature, whether accrued, absolute, contingent, or otherwise, including,
     without limitation, tax liabilities, due or to become due or arising out of
     transactions entered into or any state of facts existing prior thereto,
     other than obligations arising after the date thereof in the ordinary
     course of business.

          (i) Absence of Certain Changes or Events. Except as set forth on
     Schedule 4(i), since August 31, 2006, the Company and each Subsidiary has
     operated its business in the ordinary course and has not suffered any
     Material Adverse Effect, and there has not


                                       6



     occurred any event, change or development which has had, or which could
     reasonably be expected to have, individually or in the aggregate, a
     Material Adverse Effect or which could, individually or in the aggregate,
     reasonably be expected to prevent or materially interfere with or delay the
     consummation of the transaction contemplated hereby. Without limiting the
     generality of the foregoing, except as set forth on Schedule 4(i), since
     August 31, 2006, neither the Company nor any Subsidiary has:

               (i) made any change in its authorized capital or outstanding
          securities;

               (ii) issued, sold, delivered or agreed to issue, sell or deliver
          any capital stock, bonds or other securities or equity interests,
          including convertible securities, (whether authorized and unissued or
          held in the treasury), or granted or agreed to grant any options,
          warrants or other rights calling for the issue, sale or delivery
          thereof;

               (iii) borrowed or agreed to borrow any funds or incurred, or
          become subject to, any obligation or liability (absolute or
          contingent), except obligations and liabilities incurred in the
          ordinary course of business, consistent with past practices, none of
          which are, individually or in the aggregate, materially adverse;

               (iv) declared, set aside, made, or agreed to make distributions
          of any assets of any kind whatsoever in respect of its capital stock
          or equity interests, or purchased, redeemed or otherwise acquired, or
          agreed to purchase, redeem or otherwise acquire, any of its
          outstanding capital stock or equity interests;

               (v) unless replaced with assets, property or rights of equal or
          greater value, sold, transferred or otherwise disposed of, or agreed
          to sell, transfer or otherwise dispose of any of its assets, property
          or rights, or disposed of any inventory except in the ordinary course
          of business consistent with past practices;

               (vi) entered or agreed to enter into any agreement or arrangement
          granting any preferential rights to purchase any of its assets,
          property or rights, including inventories, or requiring the consent of
          any party to the transfer and assignment of any of such assets,
          property or rights;

               (vii) other than in the ordinary course of business, consistent
          with past practices, made or permitted, or agreed to make or permit,
          any amendment or termination of any contract, agreement or license to
          which it is a party or by which it or any of its properties are
          subject;

               (viii) made, directly or indirectly, any accrual or arrangement
          for or payment of bonuses or special compensation of any kind or any
          severance or termination pay to any present or former officer,
          director or employee of the Company;


                                       7



               (ix) granted any raises to employees, increased the rate of
          compensation payable or to become payable to any of its stockholders,
          officers, directors or employees or adopted any new, or made any
          increase in any, profit sharing, bonus, deferred compensation,
          savings, insurance, pension, retirement or other employee benefit plan
          payment or arrangement made to, for or with any of such stockholders,
          officers, directors or employees;

               (x) merged or consolidated, or agreed to merge or consolidate,
          with any other corporation or entity, or acquired or agreed to acquire
          any corporation, association, partnership, joint venture, limited
          liability company or other entity;

               (xi) created, incurred, assumed or guaranteed any indebtedness
          for money borrowed, or mortgaged, pledged or subjected to any lien,
          pledge, mortgage, security interest, conditional sales contract or
          other encumbrance of any nature whatsoever, any of its assets or
          properties, other than liens, if any, for current Taxes not yet due
          and payable;

               (xii) waived any rights of substantial value, whether or not in
          the ordinary course of business;

               (xiii) suffered any damage, destruction or loss, whether or not
          covered by insurance, which could have a Material Adverse Effect, or
          suffered any repeated, recurring or prolonged shortage, cessation or
          interruption of inventory shipments, supplies or utility services
          required to conduct its business and operations or suffered any change
          in its financial condition or in the nature of its business or
          operations which has had or could have a Material Adverse Effect;

               (xiv) amended or modified, or granted any material exception to
          its credit criteria for new or existing customers;

               (xv) materially changed any of the accounting principles followed
          by it or the methods of applying such principles, except as required
          by GAAP and disclosed in the Financial Statements;

               (xvi) changed its method of billing or collecting accounts
          receivable;

               (xvii) entered into any transaction other than in the ordinary
          course of business consistent with past practice;

               (xviii) made any commitment to make any capital expenditures;

               (xix) had any condemnation proceedings commenced with respect to
          any of its assets or property, including, without limitation, any Real
          Property (as defined in Section 4(q)); or


                                       8



               (xx) entered into any agreement or commitment, whether oral or in
          writing, to take any action described in this Section 4(i).

          (j) Assumptions or Guaranties of Indebtedness of Other Persons. Except
     as set forth on Schedule 4(j), neither the Company nor any Subsidiary has
     assumed, guaranteed, endorsed or otherwise become directly or contingently
     liable for (including without limitation, liability by way of agreement,
     contingent or otherwise, to purchase, to provide funds for payment, to
     supply funds to or otherwise invest in any debtor or otherwise to assure
     any creditor against loss), any indebtedness of any other person or entity.

          (k) Inventory and Accounts Receivable.

               (i) Each of the Company and the Subsidiaries has adequate and
          sufficient inventories of supplies for the conduct of its business in
          the ordinary course, and all inventories of the Company and the
          Subsidiaries are in good, usable and merchantable condition.

               (ii) The accounts receivable (including any loans receivable and
          advances) of the Company: (A) are lawful and valid; (B) have arisen
          out of bona fide transactions in the ordinary course of business; (C)
          have sufficient consideration, and (D) are not subject to any offset,
          allowance, credit, refund, counterclaim or similar diminution or
          discount, whether customary in the trade or otherwise except as set
          forth in the Company's books and records and for which adequate
          reserves have been established in accordance with GAAP. To the
          knowledge of the Stockholders, there are no facts or circumstances
          (other than general economic conditions) which would result in any
          material increase in the uncollectability of such receivables, in
          excess of the reserves set forth on the Financial Statements.

          (l) Contracts.

               (i) Set forth on Schedule 4(l) is a complete list of all
          contracts, agreements, leases, instruments, understandings and
          arrangements, either oral or in writing, effective beyond the
          Effective Date to which the Company or any Subsidiary is a party or by
          which the Company or any Subsidiary is bound, including, without
          limitation, all non-competition agreements with current and former
          employees, except for open purchase or sales orders for less than
          $25,000 (collectively, the "Contracts"). A true and correct copy of
          each of the Contracts, or a description of any oral Contract, has been
          furnished by the Stockholders to Buyer.

               (ii) Except as set forth on Schedule 4(l), (A) the Company (or a
          Subsidiary, as applicable), and to the knowledge of the Stockholders
          any other party, to any of the Contracts, is not in default (and no
          event has occurred which, with notice or lapse of time or both, would
          put the Company (or Subsidiary) or such other party in default) in the
          performance of any of their respective obligations under any


                                       9



          of the Contracts, nor has there occurred any event giving others (with
          notice or lapse of time or both) any rights of termination, amendment,
          acceleration or cancellation of, any Contract; (B) each Contract is
          valid, binding and enforceable and in full force and effect; (C)
          neither Stockholder has any knowledge of any breach or anticipated
          breach by any other party to any Contract; (D) no approval or consent
          of any person is needed in order that the Contracts may continue in
          full force and effect following the Effective Date and the
          consummation of the transactions contemplated hereby; (E) the
          Contracts will continue to be valid, binding and enforceable and in
          full force and effect immediately following the Effective Date in
          accordance with the terms and conditions thereof as in effect
          immediately prior to the Effective Date and the change in ownership of
          the Company pursuant to this Agreement will not result in the
          termination of, or result in a right of termination under, any
          Contract; and (F) the Company (or any Subsidiary) has not delivered or
          received any notice of termination or intention to terminate or amend
          in an adverse manner any Contract.

          (m) Assets and Properties. Except as set forth on Schedule 4(m), (A)
     the Company and each Subsidiary has good, valid and record title to and
     beneficial ownership of all of its assets and properties and will retain
     after the Effective Date all of such assets and properties, free and clear
     of all liens, charges, claims and encumbrances of any nature; (B) the
     assets include all equipment currently used by the Company and each
     Subsidiary to conduct its business in the ordinary course, are sufficient
     to operate the Company's business after the Effective Date and are in good
     condition (ordinary wear and tear excluded); (C) the Company and each
     Subsidiary as of the Effective Date will not have any liabilities or
     obligations of any nature, whether accrued, absolute, contingent, or
     otherwise, including without limitation, Tax liabilities, due or to become
     due, which shall create, give rise to or result in a lien or encumbrance on
     its assets or properties; and (D) the Company and each Subsidiary owns or
     leases, or has rights to use, all material assets and properties sufficient
     for the conduct of its business as presently conducted.

          (n) Litigation; and Claims. Except as set forth on Schedule 4(n),
     there is no suit, action or legal, administrative, arbitration, mediation,
     investigation or other proceedings of any nature pending, or to the
     knowledge of the Stockholders threatened, (A) against the Company, any
     Subsidiary or either Stockholder; (B) which affects in any way the Company,
     any Subsidiary or either Stockholder; or (C) which would materially and
     adversely affect the legality or validity of this Agreement or the
     consummation of the transactions contemplated hereby, or the continued
     operations and earnings of the Company and the Subsidiaries.

          (o) Taxes.

               (i) The Company and each Subsidiary has (A) accurately prepared
          and timely filed with the appropriate governmental agencies all Tax
          Returns required to be filed by it; (B) paid, or made provision for
          the payment of, all Taxes, including all appropriate estimated Taxes,
          which have become due or will become due for the period or periods
          ending before the Effective Date, pursuant to its Tax Returns or


                                       10



          pursuant to any assessment against it, or pursuant to any Federal,
          state or local law, including, without limitation, Federal, state and
          local income taxes, payroll withholding and unemployment taxes, and
          sales, use, excise and property taxes; and (C) withheld or collected
          all Taxes, to the extent required, and such Taxes have been paid to
          the proper governmental authorities.

               (ii) None of the Federal, state, local or other income, sales or
          other Tax Returns of the Company or any Subsidiary have been audited
          or investigated by the Internal Revenue Service or other appropriate
          taxing authorities, and to the knowledge of the Stockholders no audit
          or investigation is threatened or contemplated. The Stockholders have
          provided Buyer with true and complete copies of the Federal and state
          income tax returns of the Company and the Subsidiaries, on a
          consolidated basis, for the past three (3) years.

               (iii) There are no liens in favor of governmental agencies or
          authorities upon any of the assets or properties of the Company or any
          Subsidiary, other than with respect to Taxes not yet due and payable

               (iv) Neither the Company nor any Subsidiary has: (A) received
          written notice from any jurisdiction that the jurisdiction believes
          that the Company or Subsidiary was required to file any Tax Return
          that was not filed; (B) received a proposed assessment of Tax against
          the Company or Subsidiary or any of its assets or properties; (C)
          waived any statute of limitations with respect to Taxes or agreed to
          an extension of time with respect to a Tax assessment or deficiency;
          and (D) been a United States real property holding corporation within
          the meaning of Section 897(c)(2) of the Code during the applicable
          period specified in Section 897(c)(l)(A)(ii) of the Code.

               (v) Neither the Company nor any Subsidiary is: (A) a party to, or
          bound by, or has any obligation under, any Tax allocation or sharing
          agreement or similar contract or arrangement or any agreement that
          obligates it to make any payment computed by reference to the Taxes,
          taxable income or taxable losses of any other Person; and (B) (I) is
          or has ever been a member of an affiliated group of corporations
          filing a consolidated Federal income tax return, other than a group
          the common parent of which was the Company, or (II) has any liability
          for the Taxes of any person or entity (other than the Company) under
          Treasury Regulations Section 1.1502-6 (or any similar provision of any
          state, local, or foreign law), as a transferee or successor, by
          contract, or otherwise; and (C) a "consenting corporation" within the
          meaning of Section 341(f) of the Code, and none of the assets of the
          Company or any Subsidiary is subject to an election under Section
          341(f) of the Code.

               (vi) Neither the Company nor any Subsidiary will be required to
          include any item of income in, or exclude any item of deduction from,
          taxable income for any taxable period (or portion thereof) ending
          after the Effective Date


                                       11


          as a result of any (A) change in method of accounting for a taxable
          period ending on or prior to the Effective Date; (B) "closing
          agreement" as described in Section 7121 of the Code (or any
          corresponding or similar provision of state or local income tax law)
          executed on or prior to the Closing Date; (C) intercompany
          transactions or any excess loss account described in Treasury
          Regulations under Section 1502 of the Code (or any corresponding or
          similar provision of state or local income tax law); (D) installment
          sale or open transaction disposition made on or prior to the Closing
          Date; or (E) prepaid amount received on or prior to the Closing Date.

               (viii) Neither the Company nor any Subsidiary has distributed
          stock or equity interests of another entity, or has had its stock or
          equity interests distributed by another person or entity, in a
          transaction that was purported or intended to be governed in whole or
          in part by Section 355 or Section 361 of the Code.

               (ix) Each Stockholder, severally and not jointly, represents and
          warrants that such Stockholder has, with respect to the portion of the
          Company's income allocated to such Stockholder, (A) accurately
          prepared and timely filed with the appropriate governmental agencies
          all Tax Returns required to be filed by him; (B) paid, or made
          provision for the payment of, all Taxes, including all appropriate
          estimated Taxes, which have become due or will become due for the
          period or periods ending on or before the Closing, pursuant to those
          returns or pursuant to any assessment against him or pursuant to any
          Federal, state or local law, including, without limitation, Federal,
          foreign, state and local income taxes, excise and property taxes; and
          (C) withheld or collected all Taxes, to the extent required, and such
          Taxes have been paid to the proper governmental authority. None of the
          Federal, foreign, state, local or other income or other Tax Returns of
          such Stockholder have been audited or investigated by the Internal
          Revenue Service or other appropriate foreign, state or local taxing
          authorities, and to the knowledge of such Stockholder no audit or
          investigation is threatened or contemplated. No Stockholder has
          received written notice from any jurisdiction that the jurisdiction
          believes that the Company or any Subsidiary was required to file any
          Tax Return that was not filed.

               (x) "Tax" or "Taxes" shall mean (i) all taxes, charges, fees,
          levies or other assessments, including, without limitation, income,
          gross receipts, excise, real and personal property, profits,
          estimated, severance, occupation, production, capital gains,
          employment, withholding, stamp, value added, alternative or add-on
          minimum, sales, transfer, use, license, payroll and franchise taxes or
          any other tax, custom, duty or governmental fee, or other like
          assessment or charge of any kind whatsoever, imposed by the United
          States, or any state, county, local or foreign government or
          subdivision or agency thereof, and such term shall include any
          interest, penalties or additions to tax attributable to such taxes,
          charges, fees, levies or other assessments and any obligations under
          any agreements or


                                       12



          arrangements with any other Person with respect to such amounts and
          including any liability for taxes of a predecessor entity; and (ii)
          all obligations, including joint and several liability pursuant to the
          law of any jurisdiction or otherwise, for the payment of any of the
          types of taxes referred to in clause (i) of this definition as a
          result of being a member of an affiliated, consolidated, combined, or
          unitary group for any taxable period. "Tax Returns" shall mean any
          report, return, declaration or other information required to be
          supplied to any taxing authority in connection with Taxes (including
          any attached schedules), including, without limitation, any
          information return, claim for refund, amended return and declaration
          of estimated Tax.

          (p) No Change in Business. To the knowledge of the Stockholders,
     neither the execution of this Agreement nor the consummation of the
     transactions contemplated hereby will result in any cancellations or
     withdrawals of any business from the Company's or any Subsidiary's clients,
     suppliers or customers.

          (q) Real Estate.

               (i) Owned Real Property.

                    (A) Neither the Company nor any Subsidiary owns any real
               property or has any pending contract or agreement to purchase any
               real property.

               (ii) Leased Real Property.

                    (A) Set forth on Schedule 4(q) is a list of all the real
               property leased by the Company or any Subsidiary (the "Leased
               Real Property"). A true and correct copy of the lease agreements
               related to the Leased Real Property has been furnished by the
               Stockholders to Buyer.

                    (B) All rent, tenant reimbursables and other charges owed by
               the Company or any Subsidiary with respect to the Leased Real
               Property for all periods prior to the Effective Date have been
               paid in full.

               (iii) Condition of Leased Real Property. To the knowledge of the
          Stockholders, all Leased Real Property (including the improvements
          located thereon) is in good operating condition and repair, including,
          without limitation, all equipment, electrical, plumbing, sewerage and
          other facilities and utility systems, consistent with its present use
          and has full legal and practical access to public roads or streets and
          has all utilities and services necessary for the proper and lawful
          conduct and operation of the business of the Company or Subsidiary as
          presently utilized. To the knowledge of the Stockholders, all Leased
          Real Property and the use thereof for the business of the Company or
          Subsidiaries conform in all material respects to all applicable
          Federal, state and local laws,


                                       13



          ordinances and regulations, including, without limitation, building
          and zoning laws, OSHA regulations and the Americans with Disabilities
          Act, and neither the Company nor the Stockholders have received any
          notice from any governmental authority or any insurance rating bureau
          that any of the Leased Real Property or the use thereof for the
          business of the Company or Subsidiaries do not so conform.

          (r) Environmental Matters.

               (i) Neither the Company nor any Subsidiary has caused or allowed
          any violation of applicable environmental laws, including, without
          limitation, (i) any "hazardous waste" as defined by the Resource
          Conservation and Recovery Act of 1976, as amended from time to time,
          and regulations promulgated thereunder; (ii) any "hazardous substance"
          as defined by the Comprehensive Environmental Response, Compensation
          and Liability Act of 1980, as amended from time to time, and
          regulations promulgated thereunder; and (iii) any substance the
          presence of which is prohibited or regulated by any Federal, state or
          local law, ruling, rule or regulation similar or dissimilar to those
          set forth in this Section 4(r) ("Environmental Laws"), other than such
          products as are used in the business of the Company and the
          Subsidiaries in the ordinary course thereof and in compliance with all
          applicable laws, rules, regulations and orders. To the knowledge of
          the Stockholders, there has not been any release, threat of release,
          discharge, emission or spill of any hazardous substance on, under,
          above or from any Leased Real Property which violates any
          Environmental Law.

          (s) Insurance.

               (i) The Company has in place public liability, casualty and other
          insurance coverage insuring the inventories, work in process,
          properties, assets, business and operations of the Company and the
          Subsidiaries and its and their potential liabilities to third parties,
          and all general liability policies maintained by the Company are in an
          amount and on such terms as are reasonable and customary for
          businesses of the type conducted by the Company and the Subsidiaries.
          Since the date of its organization, the Company and each Subsidiary
          has been covered by insurance policies in scope and amount customary
          and reasonable for the business in which it has engaged since such
          date.

               (ii) Schedule 4(s) sets forth a complete and correct list of all
          current policies of theft, fire, liability, workmen's compensation,
          life, property, casualty, products liability and other insurance owned
          or held by the Company and the Subsidiaries and for each policy
          specifies the insurer, the type of insurance, the amount of coverage,
          the expiration date, the policy number, and any pending claims not
          wholly covered as to amount thereunder. All such policies are in full
          force and effect, are sufficient for compliance by the Company and the
          Subsidiaries with all requirements of law and all agreements to which
          the Company or any Subsidiary is a party (including, without
          limitation, the Contracts), and are valid, outstanding and


                                       14



          enforceable policies. Attached to Schedule 4(s) is a certificate(s) of
          insurance, issued within the past thirty (30) days by the Company's
          insurance company, with respect to the insurance policies relating to
          the Real Property. The Stockholders have delivered to Buyer true and
          correct copies of each insurance policy listed on Schedule 4(s).

               (iii) There are no outstanding unpaid insurance premiums, and
          there are no provisions for retrospective premium adjustments with the
          sole exception of worker's compensation insurance which, by law, is
          subject to audit and adjustment in subsequent time periods. If there
          are any provisions for retrospective premium adjustments contained in
          any of such policies, the Stockholders shall pay all such premium
          adjustments which relate to periods prior to the Effective Date, as
          and when assessed.

               (iv) No notice of cancellation or non-renewal of, or disallowance
          of any claim under, any such policy or binder has been received.

               (v) Neither the Company nor any Subsidiary nor, to the knowledge
          of the Stockholders, any other party to any insurance policy is in
          breach or default with respect to such insurance policy (including
          with respect to the payment of all premiums due and payable and the
          giving of notices thereunder), and no event has occurred which, with
          notice or the lapse of time or both, would constitute such a breach or
          default, or permit termination, modification or acceleration, under
          each such policy. Since the respective dates of such policies, no
          notice of cancellation or non-renewal with respect to any such policy
          has been received by the Company or any Subsidiary. Neither the
          Company nor any Subsidiary has received any letters relating to
          reservations of rights.

               (vi) Except as set forth on Schedule 4(s), there are no
          self-insurance arrangements affecting the Company or any Subsidiary.

          (t) Employees; and Employee Benefit Plans.

               (i) Set forth on Schedule 4(t) are the names of all employees of
          the Company and each Subsidiary, his or her rate of compensation, and
          the department in which he or she works. Keller(R) Team Member
          Handbook for Keller Laboratories, Inc. (A division of Keller Group,
          Inc.), which is incorporated herein by reference, provides a
          description of all fringe benefits, and a description of any plans
          providing pensions, profit-sharing, insurance benefits or any other
          similar type of fringe benefits to which the Company or any Subsidiary
          is a party or committed either orally, in writing or by law, including
          all employee benefit plans ("Employee Benefit Plans"), as defined in
          Section 3(3) of the Employee Retirement Income Security Act of 1974,
          as amended ("ERISA"), established by the Company or any Subsidiary or
          to which the Company or any Subsidiary contributes or is or has been
          required to contribute.


                                       15



               (ii) The Employee Benefit Plans and the related trusts comply and
          have complied in all material respects with the provisions of ERISA
          and all other applicable laws, rules and regulations, and all
          necessary governmental approvals for the Employee Benefit Plans have
          been obtained, including, without limitation, qualification of the
          Employee Benefit Plans under the Internal Revenue Code of 1986, as
          amended. The Employee Benefit Plans have been administered to date in
          compliance with the requirements of ERISA, and all amendment thereto
          required by law have been duly and timely adopted by the Company or
          Subsidiary, as applicable. True and complete copies of all reports or
          other documents filed with the Internal Revenue Service or the
          Department of Labor with respect to the Employee Benefit Plans have
          been delivered by the Stockholders to Buyer. Since December 31, 1974,
          no fiduciary of the Employee Benefit Plans has engaged in any
          "prohibited transaction" (as defined in ERISA), no "reportable event"
          (as defined in Section 4043(b) of ERISA) has occurred with respect to
          the Employee Benefit Plans and there is no unfunded vested liability
          with respect to the Employee Benefits Plans. Neither the Company nor
          any Subsidiary (nor any entity within the same group of trades or
          businesses under common control, within the meaning of ERISA Section
          4001(b)(1), as the Company or any Subsidiary) has, nor has it had, a
          material liability under Title IV of ERISA which has not been paid in
          full. Neither the Company nor any Subsidiary had any liability as of
          August 31, 2006 arising out of any Employee Benefit Plan that is
          required in accordance with GAAP to be set forth on the August 31,
          2006 Financial Statements that is not reflected thereon. There are no
          unfunded obligations relating to any Employee Benefit Plan which have
          not been accrued on the Financial Statements.

               (iii) Neither the Company nor any Subsidiary has ever maintained
          any plan or arrangement for providing medical or non-pension benefits
          to terminated or retired employees or their dependents except as
          provided in the Retirement and Stock Purchase Agreement dated December
          20, 2001 among Ronald P. Keller, William G. Keller, Thomas A. Keller
          and the Company (the "Ronald Keller Agreement").

               (iv) No stock options, stock appreciation rights or other
          equity-based awards have been issued or granted by the Company. Each
          "non-qualified deferred compensation plan" (as such term is defined
          under Section 409A(d)(1) of the Code and the guidance thereunder)
          under which the Company makes, is obligated to make or promises to
          make, payments (each, a "409A PLAN") complies in all material
          respects, in both form and operation, with the requirements of Section
          409A of the Code and the guidance thereunder. No payment to be made
          under any 409A Plan is, or to the knowledge of the Stockholders will
          be, subject to the penalties of Section 409A(a)(1) of the Code.

          (u) Labor Matters. Neither the Company nor any Subsidiary has any
     collective bargaining agreement with any labor unions. The Company and each


                                       16



     Subsidiary is currently conducting, and has at all times conducted, its
     business in compliance with all Federal, state and local statutes, laws,
     rules, ordinances and regulations respecting employment and employment
     practices, discrimination (including, without limitation, discrimination on
     the basis of age, gender, race or national origin), sexual harassment,
     terms and conditions of employment and wages, hours, benefits, equal
     employment opportunity, immigration and workers' compensation or otherwise,
     and there are no claims, notices and communications received from Federal
     or state officials with respect to violations of any such laws which are
     unremedied, nor has the Company or any Subsidiary received any claims,
     notices, or other instruments, asserting violation of any such laws, rules
     and regulations whether oral or in writing, from any of its present or
     former employees, which is unresolved as of the date hereof. Neither the
     Company nor any Subsidiary is engaged in any unfair labor practices.
     Neither the Company nor any Subsidiary is a party to, or otherwise bound
     by, any consent decree with, or citation by, any governmental agency or
     authority relating to employees or employment practices. Neither the
     Company nor any Subsidiary is liable for any severance pay or other
     payments to any employee or former employee arising from the termination of
     employment, nor will the Company or any Subsidiary have any liability under
     any benefit or severance policy, practice, agreement, plan, or program
     which exists or arises, or may be deemed to exist or arise, under any
     applicable law or otherwise, as a result of or in connection with the
     transactions contemplated hereunder or the termination of any of the
     Employees on or prior to the Closing Date. Neither the Company nor any
     Subsidiary has closed any plant or facility, effectuated any layoffs of
     employees or implemented any early retirement, separation or window program
     within the past three years, nor has the Company or any Subsidiary planned
     or announced any such action or program for the future. There are no
     pending or, to the knowledge of the Stockholders, threatened: (i) actions,
     complaints, charges, inquiries, proceedings or investigations by or on
     behalf of any employee, prospective employee, former employee, labor
     organization or other representative of the employees; (ii) grievances or
     arbitration proceedings which, if adversely decided, may reasonably,
     individually or in the aggregate, create a liability or cause the Company
     or any Subsidiary to incur expenses or forgo operating savings; (iii)
     unfair labor practice charges or complaints, disputes or grievances; (iv)
     campaigns being conducted to solicit cards from any employees of the
     Company or any Subsidiary to authorize representation by any labor
     organization, and no such campaigns have been conducted within the past
     three years; or (v) strikes, slow-downs, work stoppages, disputes,
     lockouts, labor controversies or threats thereof, and neither the Company
     nor any Subsidiary has experienced any such labor controversy within the
     past three years.

          (v) Product Liability and Recalls. Neither the Company nor any
     Subsidiary has any liability under any pending or, to the knowledge of the
     Stockholders, threatened claims for any injury to individuals or property
     as a result of the ownership, possession or use of any product manufactured
     or sold by the Company or any Subsidiary. Schedule 4(v) sets forth all
     voluntary, involuntary, pending and threatened recalls relating to or
     carried out by the Company or any Subsidiary.


                                       17



          (w) Transactions with Affiliates. Except as set forth on Schedule
     4(w), no Stockholder, or director or officer of the Company or any
     Subsidiary, nor any member of his or her immediate family, owns or has,
     directly or indirectly, any ownership or other interest in any business,
     other entity or otherwise, which is a party to, or in any asset or property
     which is the subject of, agreements, arrangements or other relationships of
     any kind with the Company or any Subsidiary.

          (x) Books and Records. The books of account, ledgers, order books and
     other records and documents of the Company and the Subsidiaries accurately
     and completely reflect all material information relating to the business
     and affairs of the Company and the Subsidiaries. The Company maintains
     books and records and internal accounting controls which provide reasonable
     assurance that (i) all transactions to which the Company or any Subsidiary
     is a party or by which its properties are bound are executed with
     management's authorization; (ii) the recorded accounting of the Company's
     consolidated assets is compared with existing assets at regular intervals;
     (iii) access to the Company's consolidated assets is permitted only in
     accordance with management's authorization; and (iv) all transactions to
     which the Company or any Subsidiary is a party or by which its properties
     are bound are recorded as necessary to permit preparation of the financial
     statements of the Company in accordance with GAAP.

          (y) Brokerage. Neither the Stockholders nor the Company nor any
     Subsidiary has engaged the services of any broker, investment banker,
     financial advisor, finder or other person or entity entitled to be paid a
     commission, fee or other compensation in connection with the transactions
     provided for in this Agreement.

          (z) Lines of Credit. Set forth on Schedule 4(z) is a description in
     reasonable detail of each line of credit or other financing arrangement
     (the "Lines of Credit") which the Company and any Subsidiary has with any
     bank, financial institution or other lender, except arrangements with trade
     creditors in the ordinary course of business. Each of the Lines of Credit
     and any promissory notes or other evidences of indebtedness may be prepaid
     in whole or in part without premium or penalty.

          (aa) Disclosure. No representation or warranty made by the
     Stockholders in this Agreement or in any statement or certificate furnished
     or to be furnished to Buyer pursuant hereto or in connection herewith,
     contains or shall contain any untrue statement of a material fact or omits
     or shall omit to state a material fact necessary to make the statements
     contained therein not misleading. There is no material fact which adversely
     affects, insofar as the Stockholders can now reasonably foresee, the
     business of the Company or any Subsidiary, or its assets or properties or
     prospects, or the ability of the Stockholders to perform this Agreement or
     any of the transactions contemplated hereby in accordance with the terms
     hereof, which has not been set forth herein, in any Schedule hereto or in
     any document, certificate or statement furnished by the Stockholders to
     Buyer pursuant hereto.

     5. Buyer's Representations and Warranties. Buyer represents and warrants to
the Stockholders as follows:


                                       18



          (a) Organization and Authority. Buyer is a corporation duly organized,
     validly existing and in good standing under the laws of the Commonwealth of
     Massachusetts. Buyer has all requisite power to own its property and to
     carry on its business as presently conducted, and Buyer has complete and
     unrestricted power and authority to perform this Agreement and the
     transactions contemplated hereby.

          (b) Binding Effect. This Agreement and all other agreements, documents
     and instruments executed by Buyer in connection herewith are and will be
     the valid and binding obligations of Buyer, enforceable against Buyer in
     accordance with their respective terms, and the execution, delivery and
     performance of this Agreement, and such other agreements, documents and
     instruments executed by Buyer, and the transactions contemplated hereby and
     thereby, have been duly and validly authorized and approved by Buyer's
     Board of Directors.

          (c) Non-Contravention. The execution and delivery of this Agreement
     and all other agreements, documents and instruments to be executed in
     connection herewith, and the performance of the transactions contemplated
     hereby and thereby, do not, and will not, constitute a violation of, be a
     default under, give rise to any right of termination, cancellation or
     acceleration under, or conflict with the terms of, the Restated Articles of
     Organization or By-laws of Buyer, each as amended to date, or any contract,
     lease, indenture, agreement, order, judgment or decree to which Buyer is a
     party or by which it is bound, and does not, and will not, violate or
     constitute a default under any statute, rule, regulation, order or
     ordinance of any governmental, judicial or arbitrary body.

          (d) Litigation. There is no suit, action or legal, administrative,
     arbitration or other proceedings of any nature pending, or to the knowledge
     of Buyer, threatened, against Buyer which materially adversely affects
     Buyer, or which might materially and adversely affect the legality or
     validity of this Agreement, or the consummation of the transactions
     contemplated hereby.

          (e) Disclosure. No representation or warranty made by Buyer in this
     Agreement or in any statement or certificate furnished or to be furnished
     to the Company or the Stockholders pursuant hereto or in connection
     herewith, contains or shall contain any untrue statement of material fact
     or omits or shall omit to state a material fact necessary to make the
     statements contained herein or therein not misleading.

          (f) Brokerage. Buyer has not engaged the services of any broker,
     investment banker, financial advisor, finder, or other person or entity
     entitled to be paid a commission, fee or other compensation in connection
     with the transactions provided for in this Agreement.

     6. Conditions to Buyer's Obligations. The obligations of Buyer to
consummate the transactions contemplated by this Agreement are subject to the
satisfaction (unless waived by Buyer) on or prior to the Closing Date of each of
the following conditions:


                                       19



          (a) Representations and Warranties. All representations and warranties
     of the Stockholders set forth in this Agreement and in any statement,
     certificate or other instrument delivered to Buyer pursuant hereto or in
     connection herewith, shall have been true and correct in all material
     respects on and as of the date of this Agreement, and shall be true and
     correct in all material respects on the Closing Date and as of the
     Effective Date.

          (b) No Adverse Change. Except as set forth on Schedule 4(i), since
     August 31, 2006, there shall not have been any material damage to or loss
     or destruction of any of the Fixed Assets, or any Material Adverse Effect,
     or the imposition of any laws, rules or regulations which could have a
     Material Adverse Effect, or any suit or action brought against the Company,
     any Subsidiary, or either of the Stockholders the outcome of which could
     have a Material Adverse Effect.

          (c) Compliance with Agreement. The Stockholders shall have performed
     and complied with all of their obligations under this Agreement which are
     to be performed or complied with by them on or prior to the Closing Date
     and the Effective Date.

          (d) Proceedings and Instruments Satisfactory. All proceedings,
     corporate or other, to be taken by the Stockholders, by the Company and the
     Subsidiaries, in connection with the transactions contemplated by this
     Agreement, and all documents incident thereto, shall be satisfactory in all
     respects to Buyer.

          (e) No Litigation. No investigation, suit, action or other proceeding
     shall be threatened or pending against the Company, any Subsidiary or the
     Stockholders before any court or governmental agency which seeks to
     restrain or prohibit or obtain damages or other relief in connection with
     the performance of this Agreement or the consummation of the transactions
     contemplated hereby.

          (f) Transfer of 124 Larkin Williams, LLC Assets. The Stockholders
     shall have caused 124 Larkin Williams, LLC ("LW, LLC") to be merged with
     and into the Company. Such merger shall be for consideration and by
     documentation in form and substance satisfactory to Buyer.

          (g) Employment Agreements.

               (i)  William G. Keller shall have executed and delivered to Buyer
                    an Employment Agreement in the form of Exhibit A (the "WK
                    Employment Agreement").

               (ii) Thomas A. Keller shall have executed and delivered to Buyer
                    an Employment Agreement in the form of Exhibit B hereto (the
                    "TK Employment Agreement").


                                       20



               (iii) Each of Larry Weiss, Glen Block, Chris Cormack, Laura Eads
                    and Larry Zenk shall have executed and delivered to the
                    Company an Employment Agreement providing for their
                    continued services for a period of three (3) years after the
                    Effective Date at compensation levels consistent with past
                    practices (collectively, the "Managers' Employment
                    Agreements").

          (h) Non-Competition Agreements. Each of William G. Keller and Thomas
     A. Keller shall have executed and delivered to Buyer a Non-Competition
     Agreement in the form of Exhibit B (together, the "Non-Competition
     Agreements").

          (i) Deliveries. The Stockholders shall have delivered (or caused to be
     delivered) on or prior to the Closing Date, the following:

               (i) stock certificates representing the Shares, duly endorsed for
          transfer by the respective Stockholder to Buyer;

               (ii) the WK Employment Agreement duly executed by William G.
          Keller;

               (iii) the TK Employment Agreement duly executed by Thomas A.
          Keller;

               (iv) the Managers' Employment Agreements duly executed by each of
          the persons named in Section 6 (g)(iii) above;

               (v) the Non-Competition Agreements duly executed by William G.
          Keller and Thomas A. Keller, respectively;

               (vi) a certificate of the Secretary of the Company as to the
          Company's charter documents, by-laws and incumbency and signatures of
          the Company's officers;

               (vii) the opinion of Thompson Coburn LLP in form reasonably
          satisfactory to Buyer;

               (viii) a copy of the charter documents of the Company and each
          Subsidiary, with all amendments thereto, as certified as of a recent
          date by the Secretary of State of the State of Missouri (or other
          jurisdiction of organization);

               (ix) a certificate of the legal existence and corporate good
          standing of the Company and each Subsidiary issued as of a recent date
          by the Secretary of State of the State of Missouri (or other
          jurisdiction of organization);


                                       21



               (x) certificate(s) of good standing to do business in all foreign
          jurisdictions set forth on Schedule 4(a), issued as of a recent dated
          by the Secretary of State of each such foreign jurisdiction;

               (xi) a certificate of the tax good standing of the Company and
          each Subsidiary issued as of a recent date by the applicable tax
          authority in the State of Missouri and any other foreign jurisdiction
          where the Company or any Subsidiary files any Tax Return;

               (xii) the written resignations of all the directors of the
          Company and the Subsidiaries, as listed on Schedule 6(h)(xi), from
          their respective positions with the Company and the Subsidiaries;

               (xiii) the stock books, stock ledgers, minute books and corporate
          seal of the Company and the Subsidiaries, and all other records of the
          Company and the Subsidiaries located in the corporate premises, or
          otherwise, of the Company and the Subsidiaries;

               (xiv) A letter agreement in form satisfactory to Buyer pursuant
          to which Ronald P. Keller agrees that, upon the consummation of the
          purchase and sale of the Shares, the Ronald Keller Agreement will
          continue in full force and effect, including the Non-Competition
          Covenant set forth in Section 7 thereof, and all amounts payable under
          the Ronald Keller Agreement will continue to be paid as provided
          therein, without acceleration of any payments.

               (xv) A letter from the Company's bank stating the pay-off amount
          to pay and discharge in full the Lines of Credit; and

               (xvi) such other documents, instruments and certificates not
          inconsistent with the provisions of this Agreement, executed by the
          Company and/or the Stockholders, as Buyer shall reasonably require to
          effectuate the purposes and intent of this Agreement.

     7. Conditions to the Stockholders' Obligations. The obligations of the
Stockholders to consummate the transactions contemplated by this Agreement are
subject to the satisfaction (unless waived by the Stockholders) on or prior to
the Closing Date of each of the following conditions:

          (a) Representations and Warranties. All representations and warranties
     of Buyer set forth in this Agreement and in any statement, certificate or
     other instrument delivered to the Stockholders pursuant hereto or in
     connection herewith, shall be true and correct in all material respects on
     the Closing Date and as of the Effective Date.

          (b) Compliance with Agreement. Buyer shall have performed and complied
     with all of the obligations under this Agreement which are to be performed
     or complied with by it on or prior to the Closing Date.


                                       22



          (c) Proceedings and Instruments Satisfactory. All proceedings,
     corporate or other, to be taken by Buyer or on behalf of Buyer in
     connection with the transactions contemplated by this Agreement, and all
     documents incident thereto, shall be satisfactory in all material respects
     to the Stockholders.

          (d) No Litigation. No investigation, suit, action or other proceeding
     shall be threatened or pending against Buyer before any court or
     governmental agency which seeks to restrain or prohibit or obtain damages
     or other relief in connection with the performance of this Agreement or the
     consummation of the transactions contemplated hereby.

          (e) Employment Agreements. Buyer shall have executed and delivered the
     WK Employment Agreement and the TK Employment Agreement.

          (f) Non-Competition Agreements. Buyer shall have executed and
     delivered the Non-Competition Agreement with each Stockholder.

          (g) Deliveries. Buyer shall have delivered (or caused to be delivered)
     to the Stockholders on the Closing Date the following:

               (i) the Closing Payment;

               (ii) the WK Employment Agreement duly executed by Buyer delivered
          to William G. Keller;

               (iii) the TK Employment Agreement duly executed by Buyer
          delivered to Thomas A. Keller;

               (iv) the Non-Competition Agreement duly executed by Buyer
          delivered to William G. Keller, together with payment of $250,000;

               (v) the Non-Competition Agreement duly executed by Buyer
          delivered to Thomas A. Keller, together with payment of $250,000;

               (vi) a certificate of the Secretary of Buyer as to (A) the votes
          of Buyer's Board of Directors authorizing and approving the execution,
          delivery and performance of this Agreement and the consummation of the
          transactions contemplated hereby, and (B) the incumbency and
          signatures of Buyer's officers;

               (vii) a certificate of the legal existence and corporate good
          standing of Buyer issued as of a recent date by the Secretary of State
          of the Commonwealth of Massachusetts; and

               (viii) such other documents, instruments and certificates not
          inconsistent with the provisions of this Agreement, executed by Buyer,
          as the Company and the


                                       23



          Stockholders shall reasonably require to effectuate the purposes and
          intent of this Agreement.

     8. Survival of Representations.

          (a) Survival of Representations. All representations, warranties and
     agreements made by any party in this Agreement or pursuant hereto shall
     survive the date hereof until the date two (2) years after the Effective
     Date, excluding representations and warranties relating to Sections 4(f),
     4(g), 4(m), 4(o), 4(q), 4(r) and 4(t) which shall survive until the
     expiration of the applicable statutes of limitations with respect to such
     representation or warranty, notwithstanding any investigation by any party
     made either before or after the date hereof.

          (b) Statements as Representations. All statements contained in any
     certificate, schedule, list, document or other writing delivered pursuant
     hereto or in connection with the transactions contemplated hereby shall be
     deemed representations and warranties within the meaning of Section 8(a).

     9. Indemnification by the Stockholders.

          (a) Indemnity. The Stockholders shall indemnify, defend and hold
     Buyer, the Company and the Subsidiaries harmless from and against any and
     all claims, liabilities, obligations, losses, damages, costs or expenses
     (including reasonable legal fees, costs and expenses arising from or in
     connection with any action, suit, proceeding or claim incident to any of
     the foregoing) (collectively, "Losses") suffered by Buyer, the Company or
     any Subsidiary resulting from or which arise out of (i) any acts or
     omissions of the Company, any Subsidiary or either Stockholder arising or
     occurring prior to the Closing Date with respect to the business of the
     Company or any Subsidiary, including, without limitation, any Losses
     related to the breach of warranty with respect to the products of the
     Company or any Subsidiary or services produced or performed prior to the
     Effective Date, or any product liability claim or other liability arising
     out of defective products (net of any insurance proceeds) or services
     produced or performed by the Company or any Subsidiary prior to the
     Effective Date; (ii) any breach of any representation or warranty,
     covenant, agreement or obligation on the part of either or both of the
     Stockholders under this Agreement, any Schedule or Exhibit to this
     Agreement or under any agreement executed in connection therewith, or from
     any misrepresentation in or omission from any certificate or other
     instrument furnished to Buyer pursuant hereto or in connection herewith;
     (iii) any facts or circumstances relating to the Company or any Subsidiary
     existing or arising on or prior to the Effective Date, including, without
     limitation, tax claims, environmental claims, assessments or liabilities
     relating to tax periods ending on or prior to the Effective Date,
     liabilities under or in respect of any litigation described on Schedule
     4(n); (iv) any claims for Taxes except to the extent (i) reserved against
     in the August 31, 2006 Financial Statements and (ii) arising in the
     ordinary course of business after August 31, 2006 and reserved against in
     the books and records of the Company; and (v) any brokers' or finders' fees
     or compensation in connection with the transactions provided for in this
     Agreement by any


                                       24



     person or entity claiming a right to fees or compensation by reason of
     having been engaged by or having served any Stockholder or the Company or
     any Subsidiary. Notwithstanding the foregoing, the Stockholders shall not
     be liable for trade accounts payable to the extent such trade payables are
     included in the Closing Balance Sheet in accordance with the provisions of
     Section 2.

          (b) Payment of Losses. Subject to the provisions of Section 9(c),
     Buyer shall be reimbursed by the Stockholders on demand by Buyer for any
     Losses suffered by Buyer, the Company, or any Subsidiary with respect to
     any liability or claim to which the indemnity set forth in Section 9(a)
     relates. In addition, Buyer shall have the right to set off and deduct, the
     amount of any payment made by it or Loss suffered by or asserted against it
     with respect to any liability or claim to which the indemnity set forth in
     Section 9(a) relates, against the amount of any payment obligation of Buyer
     to the Stockholders, whether under this Agreement, including, without
     limitation, the Deferred Payments, under the WK Employment Agreement, the
     TK Employment Agreement, or otherwise.

          (c) Third-Party Claims. Should any claim be made against Buyer, the
     Company or any Subsidiary by a person not a party to this Agreement with
     respect to any matter to which the indemnity set forth in Section 9(a)
     relates (a "Third-Party Claim"), then Buyer shall promptly give the
     Stockholders written notice of any such Third-Party Claim (including all
     available information regarding the details of the Third-Party Claim). If a
     Stockholder acknowledges to Buyer in writing that such Third-Party Claim is
     subject to the indemnity set forth in Section 9(a), the Stockholder shall
     have the right to defend or settle any such Third-Party Claim, at his sole
     expense, on his own behalf and with counsel of his own choosing, which
     counsel shall be reasonably satisfactory to Buyer. In such defense or
     settlement of any Third-Party Claim, Buyer shall cooperate with and assist
     the Stockholder as is reasonable and may participate therein with its own
     counsel at its sole expense, and Buyer's written consent shall be a
     requirement to any settlement and disposition thereof, which consent shall
     not be unreasonably withheld or delayed, provided that in any such
     settlement or disposition, Buyer shall not be liable for any amounts under
     such settlement or disposition and such settlement or disposition shall
     contain a complete release of Buyer from any liability. Failure by Buyer to
     give notice within a reasonable period of time shall not constitute a
     defense, in whole or in part, to any claim for indemnification by Buyer,
     except only to the extent that such failure by Buyer shall result in a
     material prejudice to the Stockholders. If a Stockholder does not notify
     Buyer within ten (10) days after receipt of Buyer's written notice of a
     Third-Party Claim that the Stockholder intends to undertake the defense
     thereof, and that such claim is subject to the indemnity set forth in
     Section 9(a), or if after undertaking such defense the Stockholder fails to
     pursue such defense in a prudent manner, then Buyer shall have the right to
     contest, settle or compromise such Third-Party Claim, and the Stockholders,
     jointly and severally, shall indemnify Buyer for the full amount of all
     Losses paid or suffered by Buyer in respect thereof. So long as a
     Stockholder has given Buyer timely notice that the Stockholder will
     undertake the defense of the Third-Party Claim, and is defending such
     Third-Party Claim in good faith, Buyer shall not pay or settle any such
     Third-Party Claim without the consent of the defending Stockholder, which
     shall not be unreasonably withheld or delayed, unless the continued
     unresolved existence of


                                       25



     such Third-Party Claim may have, in Buyer's reasonable judgment, a material
     adverse effect on the business of Buyer, the Company or any Subsidiary, or
     on Buyer, the Company or the any Subsidiary (including, but not limited to,
     any attachment, lien or other encumbrance on Buyer, the Company or any
     Subsidiary, or their assets, any refusal of any suppliers or customers of
     Buyer, the Company or any Subsidiary to do business with Buyer, the Company
     or any Subsidiary while such Third-Party Claim is pending, or if the
     continued unresolved existence of any such Third-Party Claim would
     constitute a default or an event of default under any loan or other credit
     facilities to which Buyer, the Company or any Subsidiary is a party), in
     any of which cases Buyer shall have the right to settle such Third-Party
     Claim, and the Stockholders, jointly and severally, shall indemnify Buyer
     for the full amount of all Losses paid or suffered by Buyer, the Company
     and the Subsidiaries in respect thereof.

          (d) Cumulative Remedies. Except as expressly provided herein, the
     remedies provided to Buyer, the Company and the Subsidiaries in this
     Section 9 shall be cumulative and shall not preclude the assertion by Buyer
     of any other rights or the seeking of any other remedies against the
     Stockholders.

     10. Indemnification by Buyer.

          (a) Indemnity. Buyer shall indemnify, defend and hold the Stockholders
     harmless from and against any and all Losses suffered by the Stockholders
     resulting from (i) any breach of any representation or warranty, covenant,
     agreement or obligation on the part of Buyer under this Agreement, any
     schedule to this Agreement or under any agreement executed in connection
     herewith; (ii) any misrepresentation in or omission from any certificate or
     other instrument furnished to the Stockholders pursuant hereto or in
     connection herewith; and (iii) any claims for brokers' or finders' fees or
     compensation in connection with the transactions provided for by this
     Agreement by any person, firm, corporation or other entity claiming a right
     to fees or compensation by reason of having been engaged by or having
     served Buyer.

          (b) Payment of Losses. Subject to the provisions of Section 10(c), the
     Stockholders shall be reimbursed by Buyer on demand for any Loss suffered
     by the Stockholders with respect to any liability or claim to which the
     indemnity set forth in Section 10(a) relates.

          (c) Third-Party Claims. Should any Third-Party Claim be made against
     the Stockholders with respect to any matter to which the indemnity set
     forth in Section 10(a) relates, then the Stockholders shall promptly give
     Buyer written notice of any such Third-Party Claim and Buyer shall have the
     right to defend or settle any such Third-Party Claim, at its sole expense,
     on its own behalf and with counsel of its own choosing, which counsel shall
     be reasonably satisfactory to the Stockholders. The Stockholders agree that
     Posternak Blankstein & Lund LLP is satisfactory. In such defense or
     settlement of any claim, the Stockholders shall cooperate with and assist
     Buyer to the maximum extent reasonably possible and may participate therein
     with his or her own counsel at his or her own expense,


                                       26



     and the Stockholders' written consent shall be a requirement to any
     settlement and disposition thereof, which consent shall not be unreasonably
     withheld or delayed. Failure by the Stockholders to give notice within a
     reasonable period of time shall not constitute a defense, in whole or in
     part, to any claim for indemnification by the Stockholders, except only to
     the extent that such failure by the Stockholders shall result in a material
     prejudice to Buyer. If Buyer does not notify the Stockholders within ten
     (10) days after receipt of the Stockholders' written notice of a
     Third-Party Claim that Buyer intends to undertake the defense thereof, and
     that such claim is subject to the indemnity set forth in Section 10(a), or
     if after undertaking such defense Buyer fails to pursue such defense in a
     prudent manner, then the Stockholders shall have the right to contest,
     settle or compromise the claim and Buyer shall indemnify the Stockholders
     for the full amount of all Losses paid or suffered by the Stockholders in
     respect thereof. Notwithstanding the foregoing, so long as Buyer is
     contesting any such Third Party Claim in good faith, the Stockholders shall
     not have the right to pay or settle any such claim without the prior
     written consent of Buyer.

          (d) Cumulative Remedies. Except as expressly provided herein, the
     remedies provided to the Stockholders in this Section 10 shall be
     cumulative and shall not preclude the assertion by the Stockholders of any
     other rights or the seeking of any other remedies against Buyer.

     11. Press Releases. Because Buyer is a publicly-traded company, it is
subject to strict guidelines regarding its disclosure of the transaction
contemplated by this Agreement, and accordingly, the Stockholders agree that
they will not release, and shall not permit any person or entity to release, any
press releases or other similar announcements without Buyer's prior approval
thereof.

     12. Covenants and Agreements of the Stockholders and Buyer. The
Stockholders and Buyer agree as follows:

          (a) Tax Filing. The consummation of the transaction contemplated by
     this Agreement will be a disqualifying event and the Company's S
     Corporation election shall terminate as of the Effective Date. Buyer and
     the Stockholders agree that the Company's and the Subsidiaries' 2006 tax
     year shall be treated as two (2) tax years, the first of which ends on the
     close of business on the date immediately preceding the Effective Date (the
     "End Date") and the second of which begins on the Effective Date and ends
     on December 31, 2006. The Stockholders agree that they will cause the tax
     return for the period from January 1, 2006 to the End Date to be prepared
     and provided to Buyer, at Buyer's sole expense, for review and filing by
     Buyer in a timely manner consistent with the filing requirements under the
     Internal Revenue Code. Buyer agrees to provide to the Stockholders and
     their agents, all information available from the books of the Company, as
     reasonably requested by the Stockholders, for the preparation of that
     return.

          (b) Tax Proceedings. Buyer will have the right to represent the
     interests of the Company and any Subsidiary before any governmental
     authority with respect to any inquiry, assessment, proceeding or other
     similar event relating to any Tax filing or reporting


                                       27



     of the Company and any Subsidiaries and will have the right to control the
     defense, compromise or other resolution of any such matters, including
     responding to inquiries, filing tax returns and contesting, defending and
     resolving any assessment for additional Taxes or notice of Tax deficiency
     or other adjustment of Taxes. If the Stockholders would be required to
     indemnify Buyer, the Company or any Subsidiary pursuant to Section 9 with
     respect to such Tax matter then the Stockholders have the right (but not
     the duty) to participate in the defense of such Tax matter as provided in
     Section 9(c).

     13. Miscellaneous Provisions.

          (a) Expenses. Each party shall be responsible for all of its fees and
     expenses incurred by it in connection with the execution and delivery of
     this Agreement and the consummation of the transactions contemplated
     hereby. The Stockholders shall be responsible for all fees and expenses of
     the Company incurred prior to the Closing Date in connection with the
     execution and delivery of this Agreement and the consummation of the
     transactions contemplated hereby.

          (b) Assignability; Binding Effect. This Agreement may not be assigned
     by any of the parties hereto without the prior written consent of the other
     parties. Subject to the foregoing, this Agreement shall be binding upon,
     and inure to the benefit of, the parties hereto and their respective heirs,
     executors, administrators, successors and assigns.

          (c) Notice. All notices, payments, demands and requests required or
     permitted hereunder shall be in writing and shall be deemed duly given if
     personally delivered or sent by registered or certified mail, postage
     prepaid, return receipt requested, or by Federal Express or other
     recognized overnight express couriers, or by fax and followed by hard copy,
     to the parties hereto at the following addresses:

     IF TO THE STOCKHOLDERS: To each Stockholder at his address set forth below
                             his signature.

     WITH A COPY TO:         James L. Fogle, Esq.
                             Thompson Coburn LLP
                             One US Bank Plaza
                             St. Louis, MO 63101
                             Fax: 314-552-7035

     IF TO BUYER:            National Dentex Corporation
                             526 Boston Post Road
                             Wayland, Massachusetts 01778
                             Attn: David L. Brown,
                             President and CEO
                             Fax: (508) 358-6199

     WITH A COPY TO:         Donald H. Siegel, P.C.


                                       28



                             Posternak Blankstein & Lund LLP
                             The Prudential Tower
                             800 Boylston Street
                             Boston, MA 02199-8004
                             Fax: (617) 367-2315

          Any party hereto may change its address for notice by giving notice of
     any such change of address in the manner set forth above.

          (d) Governing Law. This Agreement and all issues related to the
     subject matter hereof shall be governed by and construed in accordance with
     the internal laws of the State of Missouri.

          (e) Consent to Jurisdiction. The parties hereto consent to the
     jurisdiction of the courts of the State of Missouri sitting in St. Louis
     County, Missouri, and the United States District Court for the Eastern
     District of Missouri sitting in St. Louis, Missouri, as well as the
     jurisdiction of all courts from which an appeal may be taken from such
     courts, for the purposes of any suit, action or other proceeding relating
     to this Agreement or with respect to any transactions contemplated hereby,
     and expressly waive any and all objections the parties hereto may have as
     to the venue of such courts to settle or adjudicate any claim or
     controversy arising hereunder.

          (f) Entire Agreement; Severability. This Agreement, together with the
     Schedules and Exhibits, the WK Employment Agreement, the TK Employment
     Agreement and the Non-Competition Agreements, sets forth the entire
     agreement and understanding among the parties as to the subject matter
     hereof and merges and supersedes all prior discussions, agreements and
     understandings with respect hereto. This Agreement and such Schedules and
     Exhibits may not be amended, changed or modified except by a written
     instrument duly executed by the parties hereto. The provisions of this
     Agreement will be deemed severable, and if any provision of this Agreement
     is held illegal, void or invalid under applicable law, such provision may
     be changed to the extent reasonably necessary to make the provision legal,
     valid and binding. If any provision of this Agreement is held illegal, void
     or invalid in its entirety, the remaining provisions of this Agreement will
     not be affected but will remain binding in accordance with their terms.

          (g) No Waiver. No waiver of any breach or default hereunder shall be
     considered valid unless in writing, and no such waiver shall be deemed a
     waiver of any subsequent breach or default and of the same or similar
     nature.

          (h) Arbitration. Except as otherwise provided in Section 2(c) with
     respect to the Closing Balance Sheet, any controversy, dispute or claim
     between the parties arising out of, related to or in connection with this
     Agreement or the performance or breach hereof shall be submitted to and
     settled by arbitration conducted by the American Arbitration Association in
     St. Louis, Missouri, in accordance with its commercial arbitration rules as
     then in effect; provided that the arbitration shall be by a single
     arbitrator mutually selected by Buyer on the


                                       29



     one hand, and Stockholders on the other hand, and if the parties do not
     agree within twenty (20) days after the date of notification of a request
     for such arbitration made by either party, the selection of the single
     arbitrator shall be made by the American Arbitration Association in
     accordance with said rules. In addition to, and not in substitution for any
     and all other relief in law or equity that may be granted by the
     arbitrator, the arbitrator may grant equitable relief and specific
     performance to compel compliance hereunder. The determination of the
     arbitrator shall be accompanied by a written opinion of the arbitrator and
     shall be final, binding and conclusive on the parties, and judgment on the
     arbitrator's award, including without limitation equitable relief and
     specific performance, may be entered in and enforced by any court having
     jurisdiction thereof. The fees and expenses of the American Arbitration
     Association and of the arbitrator shall be shared equally by Buyer on the
     one hand, and the Stockholders on the other hand. The provisions of this
     Section 13(h), shall not prohibit the parties from pursuing any injunctive
     relief, temporary restraining orders or other remedies in equity, available
     to the parties for a breach or threatened breach of this Agreement.

          (i) Further Assurances. The parties hereto agree that they will,
     without further consideration, from time to time hereafter, and at their
     own expense, execute and deliver such other documents, and take such other
     action, as may reasonably be requested in order to more effectively
     consummate the transactions contemplated hereby. The provisions hereof
     shall survive the date hereof.

          (j) Counterparts. This Agreement may be signed in any number of
     counterparts, including by facsimile, each of which shall be deemed an
     original, but all of which together shall constitute one and the same
     instrument.

                  [REMAINDER OF PAGE INTENTIONALLY LEFT BLANK]

                           [SIGNATURE PAGE TO FOLLOW]


                                       30



                  [Signature page to Stock Purchase Agreement]

        THIS AGREEMENT CONTAINS A BINDING ARBITRATION PROVISION WHICH IS
                INTENDED TO BE ENFORCEABLE BY THE PARTIES HERETO.

     IN WITNESS WHEREOF, the parties have caused this Agreement to be executed
under seal as of the date first above written.


STOCKHOLDERS:                           /s/ WILLIAM G. KELLER
                                        ----------------------------------------
                                        William G. Keller
                                        Address: 2607 Briar Valley Ct.
                                                 St. Louis, MO 63122
                                        Fax: 636-600-4206
                                        E-Mail: bkeller@kellerlab.com


                                        /s/ THOMAS A. KELLER
                                        ----------------------------------------
                                        Thomas A. Keller
                                        Address: 23 Bopp Lane
                                                 St. Louis, MO 63131
                                        Fax: 636-600-4308
                                        E-Mail: tkeller@kellerlab.com


BUYER:                                  NATIONAL DENTEX CORPORATION


                                        By: /s/ RICHARD F. BECKER, JR.
                                            ------------------------------------
                                        Name: Richard F. Becker, Jr.
                                        Title: Vice President, Treasurer and
                                               Chief Financial Officer