1
                                                                 EXHIBIT 4.5





                  AMENDED AND RESTATED SUBSIDIARIES GUARANTEE


     AMENDED AND RESTATED GUARANTEE, dated as of July 9, 1996, made by each of
the corporations that are signatories hereto (the "Guarantors"), in favor of
CHEMICAL BANK, as administrative agent (in such capacity, the "Administrative
Agent"), for the banks and other financial institutions (the "Lenders") from
time to time parties to the Credit Agreement, dated as of July 31, 1995 (as
amended, supplemented or otherwise modified from time to time, the "Credit
Agreement"), among Sybron Corporation, a Wisconsin corporation (the "Parent"),
Ormco International Corporation, a Delaware corporation ("Ormco"), Kerr
Corporation, a Delaware corporation ("Kerr"), Nalge Company, a Delaware
corporation ("Nalge"), Erie Scientific Company, a Delaware corporation
("Erie"), Barnstead Thermolyne Corporation, a Delaware corporation
("Barnstead"; Ormco, Kerr, Nalge, Erie and Barnstead are collectively referred
to herein as the "Subsidiary Borrowers"; and the Parent and the Subsidiary
Borrowers are collectively referred to herein as the "Borrowers"), the Lenders,
the Administrative Agent and Chemical Securities Inc. (currently known as Chase
Securities Inc.), as Arranger.


                             W I T N E S S E T H :


     WHEREAS, the Parent (formerly known as Sybron Corporation), the Subsidiary
Borrowers, the banks parties thereto and Chemical Bank, as agent for such
banks, are parties to that certain Credit Agreement, dated as of July 1, 1993
(as amended, supplemented or otherwise modified, the "Prior Credit Agreement")
providing for certain Loans (as defined therein) and other extensions of credit
described therein;

     WHEREAS, the Parent and the Subsidiary Borrowers have requested the
Lenders to provide credit facilities pursuant to which Loans will be made to,
and Letters of Credit will be issued for the account of, the Parent and certain
Subsidiary Borrowers;

     WHEREAS, the Parent and the Subsidiary Borrowers will use the proceeds of
the Loans in part (i) to refinance all outstanding indebtedness of the Parent
and the Subsidiary Borrowers under the Prior Credit Agreement, (ii) to finance
the acquisition (the "Nunc Acquisition") of all of the Capital Stock of Nunc
Inc., a Delaware corporation, Nunc GmbH, a German company, and Nunc AS, a
Danish company (collectively, "Nunc") and (iii) to finance the working capital
and general corporate needs, including acquisitions, of the Parent and the
Subsidiary Borrowers; and

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     WHEREAS, the Lenders are willing to make the Loans and issue and/or
participate in the Letters of Credit (as hereinafter defined) on the terms and
conditions set forth in the Credit Agreement;

     WHEREAS, the Parent owns directly or indirectly all of the issued and
outstanding stock of each Guarantor;

     WHEREAS, the Parent, the Subsidiary Borrowers and the Guarantors are
members of the same consolidated group of companies and engaged in related
businesses, and each Guarantor will derive substantial direct and indirect
benefit from the making of the Loans and the Letters of Credit; and

     WHEREAS, it is a condition precedent to the obligation of the Lenders to
make their respective extensions of credit to the Parent and the Subsidiary
Borrowers under the Credit Agreement that the Guarantors shall have executed
and delivered this Guarantee to the Administrative Agent for the ratable
benefit of the Lenders;

     NOW, THEREFORE, in consideration of the premises and to induce the
Administrative Agent and the Lenders to enter into the Credit Agreement and to
induce the Lenders to make their respective extensions of credit to the Parent
and the Subsidiary Borrowers under the Credit Agreement, the Guarantors hereby
agree with the Administrative Agent, for the ratable benefit of the Lenders, as
follows:

     1.   Defined Terms.  (a)  Unless otherwise defined herein, terms defined 
in the Credit Agreement and used herein shall have the meanings given to them in
the Credit Agreement.

     (b)  As used herein "Obligations" means (i) the unpaid principal of and
interest on (including, without limitation, interest accruing after the
maturity of the Loans and interest accruing on or after the filing of any
petition in bankruptcy, or the commencement of any insolvency, reorganization
or like proceeding, relating to the Parent or any of the Subsidiary Borrowers,
whether or not a claim for post-filing or post-petition interest is allowed in
such proceeding) the Notes and all other obligations and liabilities of the
Loan Parties to the Administrative Agent or to the Lenders, whether direct or
indirect, absolute or contingent, due or to become due, or now existing or
hereafter incurred, which may arise under, out of, or in connection with, the
Credit Agreement, the Notes, any other Loan Document and any other document
made, delivered or given in connection herewith or therewith, whether on
account of principal, interest, reimbursement obligations, fees, indemnities,
costs, expenses (including, without limitation, all fees and disbursements of
counsel to the Administrative Agent or to the Lenders) or otherwise and (ii)
all obligations of any of the Borrowers to any Lender or any Affiliate of any
Lender under 

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or in connection with any Interest Rate Agreement or foreign exchange contract.

          (c)   The words "hereof," "herein" and "hereunder" and words of
similar import when used in this Guarantee shall refer to this Guarantee as a
whole and not to any particular provision of this Guarantee, and Section and
paragraph references are to this Guarantee unless otherwise specified.

          (d)   The meanings given to terms defined herein shall be equally
applicable to both the singular and plural forms of such terms.

          2.      Guarantee.    Subject to the provisions of paragraph , each of
the Guarantors hereby, jointly and severally, unconditionally and irrevocably,
guarantees to the Administrative Agent, for the ratable benefit of the Lenders
and their respective successors, indorsees, transferees and assigns, the prompt
and complete payment and performance by the Borrowers when due (whether at the
stated maturity, by acceleration or otherwise) of the Obligations (other than
any obligations owing directly by such Guarantor as a Subsidiary Borrower).

          (b)   Anything herein or in any other Loan Document to the contrary
notwithstanding, the maximum liability of each Guarantor hereunder and under the
other Loan Documents shall in no event exceed the amount which can be guaranteed
by such Guarantor under applicable federal and state laws relating to the
insolvency of debtors.

          (c)   Each Guarantor further agrees to pay any and all expenses
(including, without limitation, all fees and disbursements of counsel) which may
be paid or incurred by the Administrative Agent or any Lender in enforcing, or
obtaining advice of counsel in respect of, any rights with respect to, or
collecting, any or all of the Obligations and/or enforcing any rights with
respect to, or collecting against, such Guarantor under this Guarantee.  This
Guarantee shall remain in full force and effect until the Obligations are paid
in full and the Commitments are terminated, notwithstanding that from time to
time prior thereto the Borrowers may be free from any Obligations.

          (d)   Each Guarantor agrees that the Obligations may at any time and
from time to time exceed the amount of the liability of such Guarantor hereunder
without impairing this Guarantee or affecting the rights and remedies of the
Administrative Agent or any Lender hereunder.

          (e)   No payment or payments made by any of the Borrowers, any of the
Guarantors, any other guarantor or any other Person or received or collected by
the Administrative Agent or any Lender from any of the Borrowers, any of the
Guarantors, any other guarantor or any other Person by virtue of any action 

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or proceeding or any set-off or appropriation or application at any time or from
time to time in reduction of or in payment of the Obligations shall be deemed to
modify, reduce, release or otherwise affect the liability of any Guarantor
hereunder which shall, notwithstanding any such payment or payments other than
payments made by such Guarantor in respect of the Obligations or payments
received or collected from such Guarantor in respect of the Obligations, remain
liable for the Obligations up to the maximum liability of such Guarantor
hereunder until the Obligations are paid in full and the Commitments are
terminated.

          (f)   Each Guarantor agrees that whenever, at any time, or from time
to time, it shall make any payment to the Administrative Agent or any Lender on
account of its liability hereunder, it will notify the Administrative Agent in
writing that such payment is made under this Guarantee for such purpose.

          3.    Right of Contribution.  Each Guarantor hereby agrees that to
the extent that a Guarantor shall have paid more than its proportionate share of
any payment made hereunder, such Guarantor shall be entitled to seek and receive
contribution from and against any other Guarantor hereunder who has not paid its
proportionate share of such payment.  Each Guarantor's right of contribution
shall be subject to the terms and conditions of Section  hereof. The provisions
of this Section shall in no respect limit the obligations and liabilities of any
Guarantor to the Administrative Agent and the Lenders, and each Guarantor shall
remain liable to the Administrative Agent and the Lenders for the full amount
guaranteed by such Guarantor hereunder.

          4.      Right of Set-off.  Upon the occurrence of any Event of
Default, each Guarantor hereby irrevocably authorizes each Lender at any time
and from time to time without notice to such Guarantor or any other Guarantor,
any such notice being expressly waived by each Guarantor, to set-off and
appropriate and apply any and all deposits (general or special, time or demand,
provisional or final), in any currency, and any other credits, indebtedness or
claims, in any currency, in each case whether direct or indirect, absolute or
contingent, matured or unmatured, at any time held or owing by such Lender to or
for the credit or the account of such Guarantor, or any part thereof in such
amounts as such Lender may elect, against and on account of the obligations and
liabilities of such Guarantor to such Lender hereunder and claims of every
nature and description of such Lender against such Guarantor, in any currency,
whether arising hereunder, under the Credit Agreement, any Note, any Loan
Document or otherwise, as such Lender may elect, whether or not the
Administrative Agent or any Lender has made any demand for payment and although
such obligations, liabilities and claims may be contingent or unmatured.  The
Administrative Agent and each Lender shall notify such Guarantor promptly of any
such set-off and the application made by the Administrative Agent or such
Lender, provided that the failure to give such notice shall not affect the
validity of such set-off and application.  The rights 

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of the Administrative Agent and each Lender under this Section are in addition
to other rights and remedies (including, without limitation, other rights of
set-off) which the Administrative Agent or such Lender may have.

          5.      No Subrogation.  Notwithstanding any payment or payments made
by any of the Guarantors hereunder or any set-off or application of funds of any
of the Guarantors by any Lender, no Guarantor shall be entitled to be subrogated
to any of the rights of the Administrative Agent or any Lender against any
Borrower or any other Guarantor or any collateral security or guarantee or right
of offset held by any Lender for the payment of the Obligations, nor shall any
Guarantor seek or be entitled to seek any contribution or reimbursement from any
Borrower or any other Guarantor in respect of payments made by such Guarantor
hereunder, until all amounts owing to the Administrative Agent and the Lenders
by the Borrowers on account of the Obligations are paid in full and the
Commitments are terminated.  If any amount shall be paid to any Guarantor on
account of such subrogation rights at any time when all of the Obligations shall
not have been paid in full, such amount shall be held by such Guarantor in trust
for the Administrative Agent and the Lenders, segregated from other funds of
such Guarantor, and shall, forthwith upon receipt by such Guarantor, be turned
over to the Administrative Agent in the exact form received by such Guarantor
(duly indorsed by such Guarantor to the Administrative Agent, if required), to
be applied against the Obligations, whether matured or unmatured, in such order
as the Administrative Agent may determine.

          6.      Amendments, etc. with respect to the Obligations; Waiver of
Rights. Each Guarantor shall remain obligated hereunder notwithstanding that,
without any reservation of rights against any Guarantor and without notice to or
further assent by any Guarantor, any demand for payment of any of the
Obligations made by the Administrative Agent or any Lender may be rescinded by
such party and any of the Obligations continued, and the Obligations, or the
liability of any other party upon or for any part thereof, or any collateral
security or guarantee therefor or right of offset with respect thereto, may,
from time to time, in whole or in part, be renewed, extended, amended, modified,
accelerated, compromised, waived, surrendered or released by the Administrative
Agent or any Lender, and the Credit Agreement, the Notes and the other Loan
Documents and any other documents executed and delivered in connection therewith
may be amended, modified, supplemented or terminated, in whole or in part, as
the Administrative Agent (or the Majority Lenders, as the case may be) may deem
advisable from time to time, and any collateral security, guarantee or right of
offset at any time held by the Administrative Agent or any Lender for the
payment of the Obligations may be sold, exchanged, waived, surrendered or
released.  Neither the Administrative Agent nor any Lender shall have any
obligation to protect, secure, perfect or insure any Lien at any time held by it
as security for the Obligations or 

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for this Guarantee or any property subject thereto.  When making any    
demand hereunder against any of the Guarantors, the Administrative Agent or any
Lender may, but shall be under no obligation to, make a similar demand on any
Borrower or any other Guarantor or guarantor, and any failure by the
Administrative Agent or any Lender to make any such demand or to collect any
payments from any such Borrower or any such other Guarantor or guarantor or any 
release of any such Borrower or such other Guarantor or guarantor shall not
relieve any of the Guarantors in respect of which a demand or collection is not
made or any of the Guarantors not so released of their several obligations or
liabilities hereunder, and shall not impair or affect the rights and remedies,
express or implied, or as a matter of law, of the Administrative Agent or any
Lender against any of the Guarantors. For the purposes hereof "demand" shall    
include the commencement and continuance of any legal proceedings.

    7.  Guarantee Absolute and Unconditional.  Each Guarantor waives any and
all notice of the creation, renewal, extension or accrual of any of the
Obligations and notice of or proof of reliance by the Administrative Agent or
any Lender upon this Guarantee or acceptance of this Guarantee, the
Obligations, and any of them, shall conclusively be deemed to have been
created, contracted or incurred, or renewed, extended, amended or waived, in
reliance upon this Guarantee; and all dealings between any of the Borrowers and
any of the Guarantors, on the one hand, and the Administrative Agent and the
Lenders, on the other hand, likewise shall be conclusively presumed to have
been had or consummated in reliance upon this Guarantee.  Each Guarantor waives
diligence, presentment, protest, demand for payment and notice of default or
nonpayment to or upon any of the Borrowers or any of the Guarantors with
respect to the Obligations.  Each Guarantor understands and agrees that this
Guarantee shall be construed as a continuing, absolute and unconditional
guarantee of payment without regard to (a) the validity, regularity or
enforceability of the Credit Agreement, any Note or any other Loan Document,
any of the Obligations or any other collateral security therefor or guarantee
or right of offset with respect thereto at any time or from time to time held
by the Administrative Agent or any Lender, (b) any defense, set-off or
counterclaim (other than a defense of payment or performance) which may at any
time be available to or be asserted by any Borrower against the Administrative
Agent or any Lender, or (c) any other circumstance whatsoever (with or without
notice to or knowledge of any Borrower or such Guarantor) which constitutes, or
might be construed to constitute, an equitable or legal discharge of any of the
Borrowers for the Obligations, or of such Guarantor under this Guarantee, in
bankruptcy or in any other instance.  When pursuing its rights and remedies
hereunder against any Guarantor, the Administrative Agent and any Lender may,
but shall be under no obligation to, pursue such rights and remedies as it may
have against the Borrower or any other Person or against any collateral
security or guarantee for the Obligations or any right of offset with respect
thereto, and any 

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failure by the Administrative Agent or any Lender to pursue
such other rights or remedies or to collect any payments from any Borrower or
any such other Person or to realize upon any such collateral security or
guarantee or to exercise any such right of offset, or any release of any of the
Borrowers or any such other Person or any such collateral security, guarantee
or right of offset, shall not relieve such Guarantor of any liability
hereunder, and shall not impair or affect the rights and remedies, whether
express, implied or available as a matter of law, of the Administrative Agent
and the Lenders against such Guarantor.  This Guarantee shall remain in full
force and effect and be binding in accordance with and to the extent of its
terms upon each Guarantor and the successors and assigns thereof, and shall
inure to the benefit of the Administrative Agent and the Lenders, and their
respective successors, indorsees, transferees and assigns, until all the
Obligations and the obligations of each Guarantor under this Guarantee shall
have been satisfied by payment in full and the Commitments shall be terminated,
notwithstanding that from time to time during the term of the Credit Agreement
the Borrowers may be free from any Obligations.

    8.  Reinstatement.  This Guarantee shall continue to be effective, or be
reinstated, as the case may be, if at any time payment, or any part thereof, of
any of the Obligations is rescinded or must otherwise be restored or returned
by the Administrative Agent or any Lender upon the insolvency, bankruptcy,
dissolution, liquidation or reorganization of any Borrower or any Guarantor, or
upon or as a result of the appointment of a receiver, intervenor or conservator
of, or trustee or similar officer for, the Borrower or any Guarantor or any
substantial part of its property, or otherwise, all as though such payments had
not been made.

    9.  Payments.  Each Guarantor hereby guarantees that payments hereunder
will be paid to the Administrative Agent without set-off or counterclaim in
U.S. Dollars at the office of the Administrative Agent located at 270 Park
Avenue, New York, New York 10017.

   10 .  Representations and Warranties.  Each Guarantor hereby represents and
warrants that:

            (a)  it is a corporation duly organized, validly existing and in
           good standing (or similar concept under applicable law) under the
           laws of the jurisdiction of its incorporation and has the corporate
           power and authority and the legal right to own and operate its
           property, to lease the property it operates and to conduct the
           business in which it is currently engaged;

            (b)  it has the corporate power and authority and the legal right to
           execute and deliver, and to perform its obligations under, this
           Guarantee, and has taken all 

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     necessary corporate action to authorize its execution, delivery and
     performance of this Guarantee;

          (c)  this Guarantee constitutes a legal, valid and binding
     obligation of such Guarantor enforceable in accordance with its terms,
     except as affected by bankruptcy, insolvency, fraudulent conveyance,
     reorganization, moratorium and other similar laws relating to or affecting
     the enforcement of creditors' rights generally, general equitable
     principles (whether considered in a proceeding in equity or at law) and an
     implied covenant of good faith and fair dealing;
        
          (d)  the execution, delivery and performance of this Guarantee will
     not violate any provision of any Requirement of Law or Contractual
     Obligation of such Guarantor and will not result in or require the
     creation or imposition of any Lien on any of the properties or revenues of
     such Guarantor pursuant to any Requirement of Law or Contractual
     Obligation of the Guarantor;
        
          (e)  no consent or authorization of, filing with, or other act by or
     in respect of, any arbitrator or Governmental Authority and no consent of
     any other Person (including, without limitation, any stockholder or
     creditor of such Guarantor) is required in connection with the execution,
     delivery, performance, validity or enforceability of this Guarantee;
        
          (f)  no litigation, investigation or proceeding of or before any
     arbitrator or Governmental Authority is pending or, to the knowledge of
     such Guarantor, threatened by or against such Guarantor or against any of
     its properties or revenues  with respect to this Guarantee or any of the
     transactions contemplated hereby or which could reasonably be expected to
     have a Material Adverse Effect; and

          (g)  it has good record and marketable title in fee simple to, or a
     valid leasehold interest in, all its real property, and good title to, or
     a valid leasehold interest in, all its other property, and none of such
     property is subject to any Lien of any nature whatsoever except as
     permitted by subsection 7.3 of the Credit Agreement.
        
          Each Guarantor agrees that the foregoing representations and 
warranties shall be deemed to have been made by such Guarantor on the date of 
each borrowing by any Borrower under the Credit Agreement on and as of the
relevant Borrowing Date as though made hereunder on and as of such date.

          11.  Authority of Administrative Agent.  Each Guarantor acknowledges 
that the rights and responsibilities of the Administrative Agent under this
Guarantee with respect to any 

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action taken by the Administrative Agent or the exercise or non-exercise by the
Administrative Agent of any option, right, request, judgment or other right or
remedy provided for herein or resulting or arising out of this Guarantee shall,
as between the Administrative Agent and the Lenders, be governed by the Credit
Agreement and by such other agreements with respect thereto as may exist from
time to time among them, but, as between the Administrative Agent and such
Guarantor, the Administrative Agent shall be conclusively presumed to be acting
as agent for the Lenders with full and valid authority so to act or refrain
from acting, and no Guarantor shall be under any obligation, or entitlement, to
make any inquiry respecting such authority.
        
          12.  Notices.  All notices, requests and demands to or upon the
Administrative Agent, any Lender or any Guarantor to be effective shall be in
writing (or by telex, fax or similar electronic transfer confirmed in writing)
and shall be deemed to have been duly given or made  when delivered by hand or
if given by mail, three days after deposited in the mails, postage prepaid, or
if by telex, fax or similar electronic transfer, when sent and receipt has been
confirmed, addressed as follows:

          (a)  if to the Administrative Agent or any Lender, at its address or
     transmission number for notices provided in or referred to in subsection 
     11.2 of the Credit Agreement; and

          (b)  if to any Guarantor, at its address or transmission number for
     notices set forth under its name below.

          The Administrative Agent, each Lender and each Guarantor may change 
its address and transmission numbers for notices by notice in the manner 
provided in this Section.

          13.  Counterparts.  This Guarantee may be executed by one or more of
the Guarantors on any number of separate counterparts, and all of said
counterparts taken together shall be deemed to constitute one and the same
instrument.  A set of the counterparts of this Guarantee signed by all the
Guarantors shall be lodged with the Administrative Agent.
        
          14.  Severability.  Any provision of this Guarantee which is 
prohibited or unenforceable in any jurisdiction shall, as to such jurisdiction,
be ineffective to the extent of such prohibition or unenforceability without
invalidating the remaining provisions hereof, and any such prohibition or
unenforceability in any jurisdiction shall not invalidate or render
unenforceable such provision in any other jurisdiction.
        
          15.   Integration.  This Guarantee represents the agreement of each
Guarantor with respect to the subject matter hereof and there are no promises
or representations by the 

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Administrative Agent or any Lender relative to the subject matter hereof not
reflected herein.
        
          16.   Amendments in Writing; No Waiver; Cumulative Remedies.  (a) 
None of the terms or provisions of this Guarantee may be waived, amended,
supplemented or otherwise modified except by a written instrument executed by
each Guarantor and the Administrative Agent, provided that any provision of
this Guarantee may be waived by the Administrative Agent and the Lenders in a
letter or agreement executed by the Administrative Agent or by telex or
facsimile transmission from the Administrative Agent.
        
          (b)  Neither the Administrative Agent nor any Lender shall by any act
(except by a written instrument pursuant to paragraph  hereof), delay,
indulgence, omission or otherwise be deemed to have waived any right or remedy
hereunder or to have acquiesced in any Default or Event of Default or in any
breach of any of the terms and conditions hereof.  No failure to exercise, nor
any delay in exercising, on the part of the Administrative Agent or any Lender,
any right, power or privilege hereunder shall operate as a waiver thereof.  No
single or partial exercise of any right, power or privilege hereunder shall
preclude any other or further exercise thereof or the exercise of any other
right, power or privilege.  A waiver by the Administrative Agent or any Lender
of any right or remedy hereunder on any one occasion shall not be construed as
a bar to any right or remedy which the Administrative Agent or such Lender
would otherwise have on any future occasion.

          (c)  The rights and remedies herein provided are cumulative, may be
exercised singly or concurrently and are not exclusive of any other rights or
remedies provided by law.

          17.  Section Headings.  The Section headings used in this Guarantee 
are for convenience of reference only and are not to affect the construction
hereof or be taken into consideration in the interpretation hereof.
        
          18.  Successors and Assigns.  This Guarantee shall be binding upon the
successors and assigns of each Guarantor and shall inure to the benefit of the
Administrative Agent and the Lenders and their successors and assigns.

          19.  Governing Law.  This Guarantee shall be governed by, and 
construed and interpreted in accordance with, the law of the State of New York.

          20.  Submission To Jurisdiction.  Each of the Guarantors hereby
irrevocable and unconditionally:

          (a) submits for itself and its property in any legal action or
     proceeding relating to this Guarantee and the other Loan Documents
     to which it is a party, or for 

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     recognition and enforcement of any judgement in respect thereof, to the
     non-exclusive general jurisdiction of the Courts of the United States of
     America for the Southern District of New York, and appellate courts from
     any thereof;
        
          (b) consents that any such action or proceeding may be brought
     in such courts and waives any objection that it may now or hereafter
     have to the venue of any such action or proceeding in any such court
     or that such action or proceeding was brought in an inconvenient
     court and agrees not to pleas or claim the same;

          (c) agrees that service of process in any such action or
     proceeding may be effected by mailing a copy thereof by registered
     or certified mail (or any substantially similar form of mail),
     postage prepaid, to such Guarantor at its address set forth under
     its signature below or at such other address of which the
     Administrative Agent shall have been notified pursuant to the terms
     of Section 12 hereof;
     
          (d) agrees that nothing herein shall affect the right to effect
     service of process in any other manner permitted by law or shall
     limit the right to sue in any other jurisdiction; and
     
          (e) waives, to the maximum extent not prohibited by law, any
     right it may have to claim or recover in any legal action or
     proceeding referred to in this subsection any special, exemplary,
     punitive or consequential damages.
     
          21. Acknowledgements.  Each Guarantor hereby acknowledges that:

          (a) it has been advised by counsel in the negotiation,
     execution and delivery of this Guarantee and the other Loan
     Documents;

          (b) neither the Administrative Agent nor any Lender has any
     fiduciary relationship with or duty to such Guarantor arising out of
     or in connection with this Guarantee or any of the other Loan
     Documents, and the relationship between the Administrative Agent and
     the Lenders, on one hand, and the Guarantors on the other hand, in
     connection herewith or therewith is solely that of creditor and
     debtor; and
     
          (c) no joint venture is created hereby or by the other Loan
     Documents or otherwise exists by virtue of the transactions
     contemplated hereby among the Lenders or among the Guarantors and
     the Lenders.

          22. WAIVERS OF JURY TRIAL.  THE GUARANTORS AND THE ADMINISTRATIVE 
AGENT AND THE LENDERS BY THEIR ACCEPTANCE HEREOF HEREBY IRREVOCABLY AND 
UNCONDITIONALLY WAIVE TRIAL BY JURY IN ANY 

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LEGAL ACTION OR PROCEEDING RELATING TO THIS GUARANTEE OR ANY OTHER LOAN
DOCUMENT AND FOR ANY COUNTERCLAIM THEREIN.

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     IN WITNESS WHEREOF, each of the undersigned has caused this Guarantee to
be duly executed and delivered by its duly authorized officer as of the day and
year first above written.

                                        SAC/THERMO-BARN, INC.              
                                        BARNSTEAD THERMOLYNE CORPORATION   
                                        BIOMOLECULAR, INC.                 
                                        SAC/ERIE, INC.                     
                                        ERIE SCIENTIFIC COMPANY            
                                        ERIE SCIENTIFIC COMPANY OF         
                                          PUERTO RICO                   
                                        EVER READY THERMOMETER CO., INC.   
                                        OWL SCIENTIFIC, INC.               
                                        RICHARD-ALLAN SCIENTIFIC COMPANY   
                                        NEW ENGLAND REAGENT LABORATORY,    
                                          INC.                          
                                        CASCO STANDARDS, INC.              
                                        THE NAUGATUCK GLASS COMPANY        
                                        METAVAC, INC.                      
                                        BEDFORD MIRROR, INC.               
                                        NALGE NUNC INTERNATIONAL           
                                          CORPORATION                   
                                        NALGE COMPANY                      
                                        NUNC INCORPORATED                  
                                        NALGE (EUROPE) INCORPORATED        
                                        I-CHEM COMPANY                     
                                        SANI-TECH, INC.                    
                                        ACUTECH PLASTICS, INC.             
                                        SYBRON DENTAL SPECIALTIES INC.     
                                        SAC/ORMCO, INC.                    
                                        ORMCO CORPORATION                  
                                        ALLESEE ORTHODONTIC APPLIANCES,    
                                          INC.                          
                                        ETM CORPORATION                    
                                        EXCELLENCE IN ENDODONTICS, INC.    
                                        ANALYTIC TECHNOLOGY CORPORATION    
                                        SAC/KERR, INC.                     
                                        KERR CORPORATION                   
                                        METREX RESEARCH CORPORATION        
                                        DEMETRON RESEARCH CORP.            
                                        BELLE DE ST. CLAIRE, INC.          
                                        SAC/COMMONWEALTH, INC.             
                                        SYBRON COMMONWEALTH HOLDINGS, INC. 
                                        SYBRON TRANSITION CORP.            
                                        MEXOSERV COMPANY                   
                                                                           
                                                                           
                                                                           
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                                        By:                           
                                        Title:                             


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                                        Address for Notices:                 
                                                                             
                                        c/o Sybron International Corporation 
                                        411 East Wisconsin Avenue, 24th Floor
                                        Milwaukee, Wisconsin  53202          
                                        Fax:  (414) 274-6561