EXHIBIT 1.1

                             ________________ Shares





                           IMPAC MEDICAL SYSTEMS, INC.


                    COMMON STOCK (Par value $0.001 per share)




                             UNDERWRITING AGREEMENT


                           Dated ______________, 2002



                               _____________, 2002

Thomas Weisel Partners LLC
U.S. Bancorp Piper Jaffray
SG Cowen Securities Corporation
c/o Thomas Weisel Partners LLC
One Montgomery Street, Suite 3700
San Francisco, California 94104

Ladies and Gentlemen:

     Introduction. IMPAC Medical Systems, Inc., a Delaware corporation (the
"Company"), proposes to issue and sell to the several underwriters named in
Schedule A hereto (the "Underwriters") an aggregate of ____________ shares of
the Common Stock, par value $0.001 per share, of the Company (the "Firm
Shares").

     Certain stockholders of the Company (the "Selling Stockholders") named in
Schedule B hereto severally propose to sell to the several Underwriters an
aggregate of ____________ shares of the Company's Common Stock, par value $0.001
per share (the "Additional Shares"), with each Selling Stockholder selling the
number of shares set forth opposite such Selling Stockholder's name in Schedule
B hereto, if and to the extent that you shall have determined to exercise, on
behalf of the Underwriters, the right to purchase such shares of common stock
granted to the Underwriters in Section 3 hereof. The Firm Shares and the
Additional Shares are hereinafter collectively referred to as the "Shares." The
shares of Common Stock, par value $0.001 per share, of the Company to be
outstanding after giving effect to the sales contemplated hereby are hereinafter
referred to as the "Common Stock." The Company and the Selling Stockholders are
hereinafter collectively referred to as the "Sellers." Thomas Weisel Partners
LLC ("Thomas Weisel Partners"), U.S. Bancorp Piper Jaffray and SG Cowen
Securities Corporation have agreed to act as representatives of the several
Underwriters (in such capacity, the "Representatives") in connection with the
offering and sale of the Shares.

     The Company has filed with the Securities and Exchange Commission (the
"Commission") a registration statement on Form S-1 (file no. 333-_____),
including a prospectus, relating to the Shares. The registration statement as
amended at the time it becomes effective, including the information (if any)
deemed to be part of the registration statement at the time of effectiveness
pursuant to Rule 430A under the Securities Act of 1933, as amended (the
"Securities Act"), is hereinafter referred to as the "Registration Statement";
the prospectus in the form first used to confirm sales of Shares is hereinafter
referred to as the "Prospectus." If the Company has filed a registration
statement to register additional shares of Common Stock pursuant to Rule 462(b)
under the Securities Act (the "Rule 462 Registration Statement"), then any
reference herein to the term "Registration Statement" shall be deemed to include
such Rule 462 Registration Statement. All references in this Agreement to the
Registration Statement, the Rule 462 Registration Statement, a preliminary
prospectus, the Prospectus, or any amendments or supplements to any of the
foregoing, shall include any copy thereof filed with the Commission pursuant to
its Electronic Data Gathering, Analysis and Retrieval System ("EDGAR").

     As part of the offering contemplated by this Agreement, Thomas Weisel
Partners has agreed to reserve out of the Shares set forth opposite its name on
Schedule A to this Agreement, up to ______________ shares, for sale to the
Company's employees, officers, and directors and other parties associated with
the



Company (collectively, "Participants"), as set forth in the Prospectus under the
heading "Underwriting" (the "Directed Share Program"). The Shares to be sold by
Thomas Weisel Partners pursuant to the Directed Share Program (the "Directed
Shares") will be sold by Thomas Weisel Partners pursuant to this Agreement at
the public offering price. Any Directed Shares not orally confirmed for purchase
by any Participants by the end of the first business day after the date on which
this Agreement is executed will be offered to the public by Thomas Weisel
Partners as set forth in the Prospectus.

     1.    Representations and Warranties of the Company. The Company represents
and warrants to and agrees with each of the Underwriters that:

           1.1   Effective Registration Statement. The Registration Statement
has become effective; no stop order suspending the effectiveness of the
Registration Statement is in effect, and no proceedings for such purpose are
pending before or, to the knowledge of the Company, threatened by the
Commission.

           1.2   Contents of Registration Statement. (i) The Registration
Statement, when it became effective, did not contain and, as amended or
supplemented, if applicable, will not contain any untrue statement of a material
fact or omit to state a material fact required to be stated therein or necessary
to make the statements therein not misleading, (ii) the Registration Statement
and the Prospectus comply and, as amended or supplemented, if applicable, will
comply in all material respects with the Securities Act and the applicable rules
and regulations of the Commission thereunder and (iii) the Prospectus does not
contain and, as amended or supplemented, if applicable, will not contain any
untrue statement of a material fact or omit to state a material fact necessary
to make the statements therein, in the light of the circumstances under which
they were made, not misleading, except that the representations and warranties
set forth in this paragraph do not apply to statements or omissions in the
Registration Statement or the Prospectus based upon information relating to any
Underwriter furnished to the Company in writing by such Underwriter through you
expressly for use therein.

           1.3   Due Incorporation. The Company has been duly incorporated, is
validly existing as a corporation in good standing under the laws of the
jurisdiction of its incorporation, has the corporate power and authority to own
its property and to conduct its business as described in the Prospectus and is
duly qualified to transact business and is in good standing in each jurisdiction
in which the conduct of its business or its ownership or leasing of property
requires such qualification, except to the extent that the failure to be so
qualified or be in good standing would not have a material adverse effect on the
Company and its subsidiaries, taken as a whole.

           1.4   Subsidiaries. Each subsidiary of the Company has been duly
incorporated, is validly existing as a corporation in good standing under the
laws of the jurisdiction of its incorporation, has the corporate power and
authority to own its property and to conduct its business as described in the
Prospectus and is duly qualified to transact business and is in good standing in
each jurisdiction in which the conduct of its business or its ownership or
leasing of property requires such qualification, except to the extent that the
failure to be so qualified or be in good standing would not have a material
adverse effect on the Company and its subsidiaries, taken as a whole. All of the
issued shares of capital stock of each subsidiary of the Company have been duly
and validly authorized and issued, are fully paid and non-assessable and are
owned directly or indirectly by the Company, free and clear of all liens,
encumbrances, equities or claims.

           1.5   Underwriting Agreement. This Agreement has been duly
authorized, executed and delivered by the Company, and is a valid and binding
agreement of the Company, enforceable in accordance with its terms, except as
rights to indemnification hereunder may be limited by applicable law and except
as the enforcement hereof may be limited by bankruptcy, insolvency,
reorganization, moratorium or other similar laws relating to or affecting the
rights and remedies of creditors or by general equitable principles.

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           1.6   Description of Capital Stock. The authorized capital stock of
the Company conforms as to legal matters to the description thereof contained in
the Prospectus.

           1.7   Authorized Stock. The shares of Common Stock outstanding prior
to the issuance of the Shares to be sold by the Company have been duly
authorized and are validly issued, fully paid and non-assessable.

           1.8   Validly Issued Shares. The Shares to be sold by the Company
have been duly authorized and, when issued and delivered in accordance with the
terms of this Agreement, will be validly issued, fully paid and non-assessable,
and the issuance of such Shares will not be subject to any preemptive or similar
rights.

           1.9   No Conflict. The execution and delivery by the Company of, and
the performance by the Company of its obligations under, this Agreement will not
contravene any provision of applicable law or the certificate of incorporation
or by-laws of the Company or any agreement or other instrument binding upon the
Company or any of its subsidiaries that is material to the Company and its
subsidiaries, taken as a whole, or any judgment, order or decree of any
governmental body, agency or court having jurisdiction over the Company or any
subsidiary, and no consent, approval, authorization or order of, or
qualification with, any governmental body or agency is required for the
performance by the Company of its obligations under this Agreement, except such
as may be required by the securities or Blue Sky laws of the various states in
connection with the offer and sale of the Shares.

           1.10  No Material Adverse Change. There has not occurred any material
adverse change or any development involving a prospective material adverse
change, in the condition, financial or otherwise, or in the earnings, business
or operations of the Company and its subsidiaries, taken as a whole, from that
set forth in the Prospectus (exclusive of any amendments or supplements thereto
subsequent to the date of this Agreement).

           1.11  Absence of Material Charges. Subsequent to the respective dates
as of which information is given in the Registration Statement and the
Prospectus, (1) the Company and its subsidiaries have not incurred any material
liability or obligation, direct or contingent, nor entered into any material
transaction not in the ordinary course of business; (2) the Company has not
purchased any of its outstanding capital stock, nor declared, paid or otherwise
made any dividend or distribution of any kind on its capital stock other than
ordinary and customary dividends; and (3) there has not been any material change
in the capital stock, short-term debt or long-term debt of the Company and its
subsidiaries, except in each case as described in the Prospectus.

           1.12  Compliance with Securities Act. Each preliminary prospectus
filed as part of the registration statement as originally filed or as part of
any amendment thereto, or filed pursuant to Rule 424 under the Securities Act,
complied when so filed in all material respects with the Securities Act and the
applicable rules and regulations of the Commission thereunder.

           1.13  Legal Proceedings; Exhibits. There are no legal or governmental
proceedings pending or, to the knowledge of the Company, threatened to which the
Company or any of its subsidiaries is a party or to which any of the properties
of the Company or any of its subsidiaries is subject that are required to be
described in the Registration Statement or the Prospectus and are not so
described or any statutes, regulations, contracts or other documents that are
required to be described in the Registration Statement or the Prospectus or to
be filed as exhibits to the Registration Statement that are not described or
filed as required.

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           1.14  Compliance with Environmental Laws. The Company and its
subsidiaries (i) are in compliance with any and all applicable foreign, federal,
state and local laws and regulations relating to the protection of human health
and safety, the environment or hazardous or toxic substances or wastes,
pollutants or contaminants ("Environmental Laws"), (ii) have received all
permits, licenses or other approvals required of them under applicable
Environmental Laws to conduct their respective businesses and (iii) are in
compliance with all terms and conditions of any such permit, license or
approval, except where such noncompliance with Environmental Laws, failure to
receive required permits, licenses or other approvals or failure to comply with
the terms and conditions of such permits, licenses or approvals would not,
individually or in the aggregate, have a material adverse effect on the Company
and its subsidiaries, taken as a whole.

           1.15  No Environmental Costs. There are no costs or liabilities
associated with Environmental Laws (including, without limitation, any capital
or operating expenditures required for clean-up, closure of properties or
compliance with Environmental Laws or any permit, license or approval, any
related constraints on operating activities and any potential liabilities to
third parties) which would, individually or in the aggregate, have a material
adverse effect on the Company and its subsidiaries, taken as a whole.

           1.16  No Registration Rights. There are no contracts, agreements or
understandings between the Company and any person granting such person the right
to require the Company to file a registration statement under the Securities Act
with respect to any securities of the Company or to require the Company to
include such securities with the Shares registered pursuant to the Registration
Statement other than as described in the Registration Statement and as have been
waived in writing in connection with the offering contemplated hereby.

           1.17  Not an Investment Company. The Company is not and, after giving
effect to the offering and sale of the Shares and the application of the
proceeds thereof as described in the Prospectus, will not be an "investment
company" as such term is defined in the Investment Company Act of 1940, as
amended.

           1.18  Good Title to Properties. The Company and its subsidiaries have
good and marketable title in fee simple to all real property and good and
marketable title to all personal property owned by them which is material to the
business of the Company and its subsidiaries, in each case free and clear of all
liens, encumbrances and defects except such as are described in the Prospectus
or such as do not materially affect the value of such property and do not
interfere with the use made and proposed to be made of such property by the
Company and its subsidiaries; and any real property and buildings held under
lease by the Company and its subsidiaries are held by them under valid,
subsisting and enforceable leases with such exceptions as are not material and
do not interfere with the use made and proposed to be made of such property and
buildings by the Company and its subsidiaries.

           1.19  Intellectual Property Rights. The Company and its subsidiaries
own or possess, or can acquire on reasonable terms, all material patents, patent
rights, licenses, inventions, copyrights, know-how (including trade secrets and
other unpatented and/or unpatentable proprietary or confidential information,
systems or procedures), trademarks, service marks and trade names currently
employed by them in connection with the business now operated by them, and
neither the Company nor any of its subsidiaries has received any notice of
infringement of or conflict with asserted rights of others with respect to any
of the foregoing which, individually or in the aggregate, if the subject of an
unfavorable decision, ruling or finding, would have a material adverse affect on
the Company and its subsidiaries, taken as a whole.

           1.20  No Labor Disputes. No material labor dispute with the employees
of the Company or any of its subsidiaries exists, or, to the knowledge of the
Company, is imminent; and the Company is not

                                                                             -4-



aware of any existing, threatened or imminent labor disturbance by the employees
of any of its principal suppliers, manufacturers or contractors that could have
a material adverse effect on the Company and its subsidiaries, taken as a whole.

           1.21  Insurance. The Company and its subsidiaries are insured by the
insurers of recognized financial responsibility against such losses and risks
and in such amounts as are prudent and customary in the businesses in which they
are engaged; and neither the Company nor any of its subsidiaries has any reason
to believe that it will not be able to renew its existing insurance coverage as
and when such coverage expires or to obtain similar coverage from similar
insurers as may be necessary to continue its business at a cost that would not
have a material adverse effect on the Company and its subsidiaries, taken as a
whole.

           1.22  Governmental Permits. The Company and its subsidiaries possess
all certificates, authorizations and permits issued by the appropriate federal,
state or foreign regulatory authorities necessary to conduct their respective
business, except where the failure to possess such certificate, authorization or
permit would not, individually or in the aggregate, have a material adverse
effect on the Company and its subsidiaries, taken as a whole. Neither the
Company nor any of its subsidiaries has received any notice of proceedings
relating to the revocation or modification of any such certificate,
authorization or permit which, individually or in the aggregate, if the subject
of an unfavorable decision, ruling or finding, would have a material adverse
effect on the Company and its subsidiaries, taken as a whole.

           1.23  Accounting Controls. The Company and each of its subsidiaries
maintain a system of internal accounting controls sufficient to provide
reasonable assurance that (1) transactions are executed in accordance with
management's general or specific authorizations; (2) transactions are recorded
as necessary to permit preparation of financial statements in conformity with
generally accepted accounting principles and to maintain asset accountability;
(3) access to assets is permitted only in accordance with management's general
or specific authorization; and (4) the recorded accountability for assets is
compared with the existing assets at reasonable intervals and appropriate action
is taken with respect to any differences.

           1.24  Directed Share Program. The Company represents and warrants to
Thomas Weisel Partners that (i) the Registration Statement, the Prospectus and
any preliminary prospectus comply, and any further amendments or supplements
thereto will comply, with any applicable laws or regulations of foreign
jurisdictions in which the Prospectus or any preliminary prospectus, as amended
or supplemented, if applicable, are distributed in connection with the Directed
Share Program, and that (ii) no authorization, approval, consent, license,
order, registration or qualification of or with any government, governmental
instrumentality or court, other than such as have been obtained, is necessary
under the securities laws and regulations of foreign jurisdictions in which the
Directed Shares are offered outside the United States.

           1.25  Compliance with Laws. To the Company's knowledge, the Company
and its subsidiaries are conducting their business in compliance with the Fair
Labor Standards Act, the rules and regulations of the federal Food and Drug
Administration, and all applicable federal, state and local laws, rules and
regulations of the jurisdictions in which it is conducting business, including,
without limitation, all applicable local, state and federal laws and regulations
governing health, sanitation, safety, environmental matters, zoning and land
use, except where the failure to be so in compliance would not have a material
adverse effect on the Company and its subsidiaries, taken as a whole.

     2.    Representations and Warranties of the Selling Stockholders.  Each of
the Selling Stockholders, severally and not jointly, represents and warrants to
and agrees with each of the Underwriters that:

                                                                             -5-



           2.1   Due Authorization. This Agreement has been duly authorized,
executed and delivered by or on behalf of such Selling Stockholder and is a
valid and binding agreement of such Selling Stockholder, enforceable in
accordance with its terms, except as rights to indemnification hereunder may be
limited by applicable law and except as the enforcement hereof may be limited by
bankruptcy, insolvency, reorganization, moratorium or other similar laws
relating to or affecting the rights and remedies of creditors or by general
equitable principles.

           2.2   Selling Stockholder Documents. The Custody Agreement and the
Power of Attorney have been duly authorized, executed and delivered by such
Selling Stockholder and are valid and binding agreements of such Selling
Stockholder enforceable in accordance with their respective terms, except as
rights to indemnification thereunder may be limited by applicable law and except
as the enforcement thereof may be limited by bankruptcy, insolvency,
reorganization, moratorium or other similar laws relating to or affecting the
rights and remedies of creditors or by general equitable principles.

           2.3   No Conflict. The execution and delivery by such Selling
Stockholder of, and the performance by such Selling Stockholder of its
obligations under, this Agreement, the Custody Agreement signed by such Selling
Stockholder and ____________, as Custodian, relating to the deposit of the
Shares to be sold by such Selling Stockholder (the "Custody Agreement") and the
Power of Attorney appointing certain individuals as such Selling Stockholder's
attorneys-in-fact to the extent set forth therein, relating to the transactions
contemplated hereby and by the Registration Statement (the "Power of Attorney")
will not contravene any provision of applicable law, or the certificate of
incorporation or by-laws of such Selling Stockholder (if such Selling
Stockholder is a corporation), or any agreement or other instrument binding upon
such Selling Stockholder or any judgment, order or decree of any governmental
body, agency or court having jurisdiction over such Selling Stockholder, and no
consent, approval, authorization or order of, or qualification with, any
governmental body or agency is required for the performance by such Selling
Stockholder of its obligations under this Agreement or the Custody Agreement or
Power of Attorney of such Selling Stockholder, except such as may be required by
the securities or Blue Sky laws of the various states in connection with the
offer and sale of the Shares.

           2.4   Good Title to Shares. Such Selling Stockholder has, and on each
Closing Date will have, valid title to the Shares to be sold by such Selling
Stockholder and the legal right and power, and all authorization and approval
required by law, to enter into this Agreement, the Custody Agreement and the
Power of Attorney and to sell, transfer and deliver the Shares to be sold by
such Selling Stockholder.

           2.5   Delivery of Common Shares. Delivery of the Shares to be sold by
such Selling Stockholder pursuant to this Agreement will pass title to such
Shares free and clear of any security interests, claims, liens, equities and
other encumbrances.

           2.6   No Registration Rights. Such Selling Stockholder does not have
any registration or other similar rights to have any equity or debt securities
registered for sale by the Company under the Registration Statement or included
in the offering contemplated by this Agreement, other than as described in the
Registration Statement and as have been waived in writing in connection with the
offering contemplated hereby.

           2.7   No Price Stabilization or Manipulation. Such Selling
Stockholder has not taken and will not take, directly or indirectly, any action
designed to or that might be reasonably expected to cause or result in
stabilization or manipulation of the price of the Common Stock to facilitate the
sale or resale of the Shares.

                                                                             -6-



           2.8   Disclosure by Selling Stockholder in Registration Statement.
Such portion of the Registration Statement comprised of the table and the notes
thereto under the caption "Principal and Selling Stockholders" in the form
supplied to such Selling Stockholders in so far as such portion specifically
related to such Selling Stockholder do not contain any untrue statement of a
material fact or omit to state a material fact required to be stated therein or
necessary to make the statements therein, in light of the circumstances under
which they were made, not misleading.

           2.9   Confirmation of Company Representations and Warranties. Each of
Joseph K. Jachinowski, James P. Hoey and David A. Auerbach (each a "Selling
Officer," and collectively the "Selling Officers") has no reason to believe that
the representations and warranties of the Company contained in Section 1 hereof
are not true and correct, is familiar with the Registration Statement and the
Prospectus and has no knowledge of any material fact, condition or information
not disclosed in the Registration Statement or the Prospectus which has had or
may have a material adverse effect on the Company and its subsidiaries, taken as
a whole, and is not prompted to sell any of the Shares by any information
concerning the Company which is not set forth in the Registration Statement and
the Prospectus.

     3.    Purchase and Sale Agreements.

           3.1   Firm Shares. The Company hereby agrees to sell to the several
Underwriters, and each Underwriter, upon the basis of the representations and
warranties herein contained, but subject to the conditions hereinafter stated,
agrees, severally and not jointly, to purchase from the Company at $______ a
share (the "Purchase Price") the number of Firm Shares set forth in Schedule A
hereto opposite the name of such Underwriter.

           3.2   Additional Shares. On the basis of the representations and
warranties contained in this Agreement, and subject to its terms and conditions,
each of the Selling Stockholders, severally and not jointly, agrees to sell to
the Underwriters the Additional Shares, and the Underwriters shall have a one
time right to purchase, severally and not jointly, up to _______________
Additional Shares at the Purchase Price. If you, on behalf of the Underwriters,
elect to exercise such option, you shall so notify the Company and the Selling
Stockholders in writing not later than thirty (30) days after the date of this
Agreement, which notice shall specify the number of Additional Shares to be
purchased by the Underwriters and the date on which such shares are to be
purchased. Such date may be the same as the Closing Date (as defined below) but
not earlier than the Closing Date nor later than ten (10) business days after
the date of such notice. Additional Shares may be purchased as provided in
Section 4 hereof solely for the purpose of covering over allotments made in
connection with the offering of the Firm Shares. If any Additional Shares are to
be purchased, each Underwriter agrees, severally and not jointly, to purchase
the number of Additional Shares (subject to such adjustments to eliminate
fractional shares as you may determine) that bears the same proportion to the
total number of Additional Shares to be purchased as the number of Firm Shares
set forth in Schedule A hereto opposite the name of such Underwriter bears to
the total number of Firm Shares.

           3.3   Market Standoff Provision. Each Seller hereby agrees that,
without the prior written consent of Thomas Weisel Partners, it will not, during
the period ending 180 days after the date of the Prospectus, (i) offer, pledge,
sell, contract to sell, sell any option or contract to purchase, purchase any
option or contract to sell, grant any option, right or warrant to purchase,
lend, or otherwise transfer or dispose of, directly or indirectly, any shares of
Common Stock or any securities convertible into or exercisable or exchangeable
for Common Stock or (ii) enter into any swap or other arrangement that transfers
to another, in whole or in part, any of the economic consequences of ownership
of the Common Stock, whether any such transaction described in clause (i) or
(ii) above is to be settled by delivery of Common Stock or such other
securities, in cash or otherwise. The foregoing sentence shall not apply to (A)
the Shares to be sold hereunder, (B) the issuance by the Company of shares of
Common Stock upon the exercise of options or

                                                                             -7-



warrants or the conversion of a security outstanding on the date hereof or under
the 2002 Employee Stock Purchase Plan, (C) the grant by the Company of options
to purchase shares of Common Stock, and the issuance of shares of Common Stock
upon the exercise of such options, pursuant to the Company's 1993 Stock Option
Plan, 1998 Stock Plan and 2002 Stock Plan, (D) transactions by any person other
than the Company relating to shares of Common Stock or other securities acquired
in open market transactions after the completion of the offering of the Shares
or (E) the issuance by the Company of Common Stock or securities convertible
into or exchangeable for Common Stock in connection with mergers or the
acquisition of securities, businesses, property or other assets, provided,
however, that any such issuance shall not amount to more than 3% of the
Company's outstanding Common Stock on the date of this Agreement. In addition,
each Selling Stockholder, agrees that, without the prior written consent of
Thomas Weisel Partners, it will not, during the period ending 180 days after the
date of the Prospectus, make any demand for, or exercise any right with respect
to, the registration of any shares of Common Stock or any security convertible
into or exercisable or exchangeable for Common Stock.

           3.4   Terms of Public Offering. The Sellers are advised by you that
the Underwriters propose to make a public offering of their respective portions
of the Shares as soon after the Registration Statement and this Agreement have
become effective as in your judgment is advisable. The Sellers are further
advised by you that the Shares are to be offered to the public initially at
$____ a share (the "Public Offering Price") and to certain dealers selected by
you at a price that represents a concession not in excess of $______ a share
under the Public Offering Price, and that any Underwriter may allow, and such
dealers may reallow, a concession, not in excess of $_____ a share, to any
Underwriter or to certain other dealers.

     4.    Payment and Delivery.

           4.1   Firm Shares. Payment for the Firm Shares to be sold by the
Company shall be made to the Company in immediately available funds against
delivery of such Firm Shares for the respective accounts of the several
Underwriters at 10:00 a.m., New York City time, on ____________, 2002, or at
such other time on the same or such other date, not later than _________, 2002,
as shall be designated in writing by you. The time and date of such payment are
hereinafter referred to as the "Closing Date."

           4.2   Additional Shares. Payment for any Additional Shares shall be
made to the Selling Stockholders in immediately available funds in New York City
against delivery of such Additional Shares for the respective accounts of the
several Underwriters at 10:00 a.m., New York City time, on the date specified in
the notice described in Section 3.2 or at such other time on the same or on such
other date, in any event not later than _______, 2002, as shall be designated in
writing by you. The time and date of such payment are hereinafter referred to as
the "Option Closing Date."

           4.3   Delivery of Certificates. Certificates for the Firm Shares and
Additional Shares shall be in definitive form and registered in such names and
in such denominations as you shall request in writing not later than one (1)
full business day prior to the Closing Date or the Option Closing Date, as the
case may be. The certificates evidencing the Firm Shares and Additional Shares
shall be delivered to you on the Closing Date or the Option Closing Date, as the
case may be, for the respective accounts of the several Underwriters, with any
transfer taxes payable in connection with the transfer of the Shares to the
Underwriters duly paid, against payment of the Purchase Price therefor.

     5.    Covenants of the Company. In further consideration of the agreements
of the Underwriters herein contained, the Company covenants with each
Underwriter as follows:

           5.1   Furnish Copies of Registration Statement and Prospectus. To
furnish to you, without charge, a signed copy of the Registration Statement
(including exhibits thereto) and for delivery to each other

                                                                             -8-



Underwriter a conformed copy of the Registration Statement (without exhibits
thereto) and to furnish to you in New York City, without charge, prior to 10:00
a.m. New York City time on the business day next succeeding the date of this
Agreement or as soon as commercially practicable and during the period mentioned
in Section 5.3 below, as many copies of the Prospectus and any supplements and
amendments thereto or to the Registration Statement as you may reasonably
request.

           5.2   Notification of Amendments or Supplements. Before amending or
supplementing the Registration Statement or the Prospectus, to furnish to you a
copy of each such proposed amendment or supplement and not to file any such
proposed amendment or supplement to which you reasonably object, and to file
with the Commission within the applicable period specified in Rule 424(b) under
the Securities Act any prospectus required to be filed pursuant to such rule.

           5.3   Filings of Amendments or Supplements. If, during such period
after the first date of the public offering of the Shares as in the opinion of
counsel for the Underwriters the Prospectus is required by law to be delivered
in connection with sales by an Underwriter or dealer (the "Prospectus Delivery
Period"), any event shall occur or condition exist as a result of which it is
necessary to amend or supplement the Prospectus in order to make the statements
therein, in the light of the circumstances when the Prospectus is delivered to a
purchaser, not misleading, or if, in the opinion of counsel for the
Underwriters, it is necessary to amend or supplement the Prospectus to comply
with applicable law, forthwith to prepare, file with the Commission and furnish,
at its own expense, to the Underwriters and to the dealers (whose names and
addresses you will furnish to the Company) to which Shares may have been sold by
you on behalf of the Underwriters and to any other dealers upon request, either
amendments or supplements to the Prospectus so that the statements in the
Prospectus as so amended or supplemented will not, in the light of the
circumstances when the Prospectus is delivered to a purchaser, be misleading or
so that the Prospectus, as amended or supplemented, will comply with law.

           5.4   Blue Sky Laws. To endeavor to qualify the Shares for offer and
sale under the securities or Blue Sky laws of such jurisdictions as you shall
reasonably request.

           5.5   Earnings Statement. To make generally available to its
securityholders as soon as practicable, but in any event not later than eighteen
(18) months after the effective date of the Registration Statement (as defined
in Rule 158(c) under the Securities Act), an earnings statement of the Company
and its subsidiaries (which need not be audited) complying with Section 11(a) of
the Securities Act and the rules and regulations thereunder (including, at the
option of the Company, Rule 158).

           5.6   Use of Proceeds. The Company shall apply the net proceeds from
the sale of the Shares sold by it in the manner described under the caption "Use
of Proceeds" in the Prospectus.

           5.7   Transfer Agent. The Company shall engage and maintain, at its
expense, a registrar and transfer agent for the Common Stock.

           5.8   Periodic Reporting Obligations. During the Prospectus Delivery
Period, the Company shall file, on a timely basis, with the Commission and the
Nasdaq National Market all reports and documents required to be filed under the
Exchange Act. Additionally, the Company shall file with the Commission such
information on Form 10-Q or Form 10-K as may be required by Rule 463 under the
Securities Act.

           5.9   Directed Share Program. That in connection with the Directed
Share Program, the Company will, upon notification, ensure that the Directed
Shares will be restricted to the extent required by the National Association of
Securities Dealers, Inc. (the "NASD") or the NASD rules from sale, transfer,

                                                                             -9-



assignment, pledge or hypothecation for a period of three (3) months following
the date of the effectiveness of the Registration Statement. Thomas Weisel
Partners will notify the Company as to which Participants will need to be so
restricted. The Company will direct the transfer agent to place stop transfer
restrictions upon such securities for such period of time. Furthermore, the
Company covenants with Thomas Weisel Partners that the Company will comply with
all applicable securities and other applicable laws, rules and regulations in
each foreign jurisdiction in which the Directed Shares are offered in connection
with the Directed Share Program.

           5.10  Exchange Act Compliance. During the Prospectus Delivery Period,
the Company will file all documents required to be filed with the Commission
pursuant to Section 13, 14 or 15 of the Exchange Age in the manner and within
the time periods required by the Exchange Act.

     6.    Conditions to the Underwriters' Obligations.  The obligations of the
Sellers to sell the Shares to the several Underwriters and the several
obligations of the Underwriters to purchase and pay for the Shares on the
Closing Date are subject to the following conditions:

           6.1   Effective Registration Statement. The Registration Statement
shall have become effective not later than __________, 2002 (New York City time)
on the date hereof.

           6.2   Rule 462 Registration Statement. If the Company elects to rely
upon Rule 462(b), the Company shall file a Rule 462 Registration Statement with
the Commission in compliance with Rule 462(b) by 10:00 P.M., Washington, D.C.
time, on the date of this Agreement, and the Company shall at the time of filing
either pay to the Commission the filing fee for the Rule 462 Registration
Statement or give irrevocable instructions for the payment of such fee pursuant
to Rule 111(b) under the Securities Act.

           6.3   Prospectus Filed with Commission. The Company shall have filed
the Prospectus with the Commission (including the information required by Rule
430A under the Securities Act) in the manner and within the time period required
by Rule 424(b) under the Securities Act; or the Company shall have filed a
post-effective amendment to the Registration Statement containing the
information required by such Rule 430A, and such post-effective amendment shall
have become effective.

           6.4   No Stop Order. No stop order suspending the effectiveness of
the Registration Statement, any Rule 462 Registration Statement, or any
post-effective amendment to the Registration Statement, shall be in effect and
no proceedings for such purpose shall have been instituted or threatened by the
Commission.

           6.5   No NASD Objection. The NASD shall have raised no objection to
the fairness and reasonableness of the underwriting terms and arrangements.

           6.6   No Debt Downgrading. There shall not have occurred any
downgrading, nor shall any notice have been given of any intended or potential
downgrading or of any review for a possible change that does not indicate the
direction of the possible change, in the rating accorded any of the Company's
securities by any "nationally recognized statistical rating organization," as
such term is defined for purposes of Rule 436(g)(2) under the Securities Act.

           6.7   No Material Adverse Change. There shall not have occurred any
change or any development involving a prospective change, in the condition,
financial or otherwise, or in the earnings, business or operations of the
Company and its subsidiaries, taken as a whole, from that set forth in the
Prospectus (exclusive of any amendments or supplements thereto subsequent to the
date of this Agreement)

                                                                            -10-



that, in your judgment, is material and adverse and that makes it, in your
judgment, impracticable to market the Shares on the terms and in the manner
contemplated in the Prospectus.

           6.8   Officer's Certificate. The Underwriters shall have received on
the Closing Date a certificate, dated the Closing Date and signed by the Chief
Executive Officer or President of the Company, to the effect set forth in
Sections 6.4 and 6.7 above and to the effect that the representations and
warranties of the Company contained in this Agreement are true and correct as of
the Closing Date (except that those representations and warranties which address
matters only as of a particular date shall remain true and correct as of such
date) and that the Company has complied in all material respects with all of the
agreements and satisfied all of the conditions on its part to be performed or
satisfied hereunder on or before the Closing Date.

           6.9   Opinion of Company Counsel. The Underwriters shall have
received on the Closing Date an opinion of Orrick, Herrington & Sutcliffe LLP,
counsel for the Company, dated the Closing Date, the form of which is attached
hereto as Exhibit A. The opinion shall be rendered to the Underwriters at the
request of the Company and shall so state therein.

           6.10  Opinion of Selling Stockholders Counsel. The Underwriters shall
have received on the Closing Date opinions of Orrick, Herrington & Sutcliffe LLP
and [Summit's counsel], counsels for the Selling Stockholders, dated the Closing
Date, the form of which is attached hereto as Exhibit B. The opinions shall be
rendered to the Underwriters at the request of the Selling Stockholders and
shall so state therein.

           6.11  Opinion of Underwriters Counsel. The Underwriters shall have
received on the Closing Date an opinion of Wilson Sonsini Goodrich & Rosati,
Professional Corporation, counsel for the Underwriters, dated the Closing Date,
covering the matters referred to in Exhibit A, paragraphs (vi), (vii), (ix) (but
only as to the statements in the Prospectus under "Description of Capital Stock"
and "Underwriters") and (xiii). With respect to paragraph (xiii) of Exhibit A,
such counsel may state that their opinion and belief are based upon their
participation in the preparation of the Registration Statement and Prospectus
and any amendments or supplements thereto and review and discussion of the
contents thereof, but are without independent check or verification, except as
specified.

           6.12  Accountant's Comfort Letter. The Underwriters shall have
received, on each of the date hereof and the Closing Date, a letter dated the
date hereof or the Closing Date, as the case may be, in form and substance
satisfactory to the Underwriters, from PricewaterhouseCoopers, LLP, independent
public accountants, containing statements and information of the type ordinarily
included in accountants' "comfort letters" to underwriters with respect to the
financial statements and certain financial information contained in the
Registration Statement and the Prospectus; provided that the letter delivered on
the Closing Date shall use a "cut-off date" not earlier than the date hereof.

           6.13  Lock-Up Agreements. The "lock-up" agreements, each
substantially in the form of Exhibit C hereto, between you and certain
stockholders, officers and directors of the Company, delivered to you on or
before the date hereof, shall be in full force and effect on the Closing Date.

           6.14  Selling Stockholders Certificate. The Underwriters shall have
received on the Option Closing Date a certificate, dated the Option Closing Date
and signed by the Attorney-in-Fact of each Selling Stockholder, to the effect
that the representations and warranties of the Selling Stockholders contained in
this Agreement are true and correct as of the Option Closing Date and that the
Selling Stockholders have complied in all material respects with all of the
agreements and satisfied all of the conditions on their part to be performed or
satisfied hereunder on or before the Option Closing Date.

                                                                            -11-



           6.15  Selling Stockholder Documents. On the date hereof, the Company
and the Selling Stockholders shall have furnished for review by the
Representatives copies of the Powers of Attorney and Custody Agreements executed
by each of the Selling Stockholders and such further information, certificates
and documents as the Representatives may reasonably request.

           6.16  Additional Documents. On the Closing Date, as applicable, the
Representatives and counsel for the Underwriters shall have received such
information, documents and opinions as they may reasonably require for the
purposes of enabling them to pass upon the issuance and sale of the Shares as
contemplated herein, or in order to evidence the accuracy of any of the
representations and warranties, or the satisfaction of any of the conditions or
agreements, herein contained.

     The several obligations of the Underwriters to purchase Additional Shares
hereunder are subject to the satisfaction of each of the above conditions on or
prior to the Option Closing Date and to the delivery to you on the Option
Closing Date of such documents as you may reasonably request with respect to the
good standing of the Company, the due authorization and issuance of the
Additional Shares and other matters related to the issuance of the Additional
Shares.

     7.    Expenses. Whether or not the transactions contemplated in this
Agreement are consummated or this Agreement is terminated, the Company agrees to
pay or cause to be paid all expenses incident to the performance of their
obligations under this Agreement, including: (i) the fees, disbursements and
expenses of the Company's counsel, the Company's accountants and counsel for the
Selling Stockholders in connection with the registration and delivery of the
Shares under the Securities Act and all other fees or expenses in connection
with the preparation and filing of the Registration Statement, any preliminary
prospectus, the Prospectus and amendments and supplements to any of the
foregoing, including all printing costs associated therewith, and the mailing
and delivering of copies thereof to the Underwriters and dealers, in the
quantities hereinabove specified, (ii) all reasonable costs and expenses related
to the transfer and delivery of the Shares to the Underwriters, including any
transfer or other taxes payable thereon, (iii) the cost of printing or producing
any Blue Sky or legal investment memorandum in connection with the offer and
sale of the Shares under state securities laws and all expenses in connection
with the qualification of the Shares for offer and sale under state securities
laws as contemplated by Section 5(d) hereof, including filing fees and the
reasonable fees and disbursements of counsel for the Underwriters in connection
with such qualification and in connection with the Blue Sky or legal investment
memorandum, (iv) all filing fees and the reasonable fees and disbursements of
counsel to the Underwriters incurred in connection with the review and
qualification of the offering of the Shares by the NASD, (v) all fees and
expenses in connection with the preparation and filing of the registration
statement on Form 8-A relating to the Common Stock and all costs and expenses
incident to listing the Shares on the Nasdaq National Market, (vi) the cost of
printing certificates representing the Shares, (vii) the costs and charges of
any transfer agent, registrar or depositary, (viii) the costs and expenses of
the Company relating to investor presentations on any "road show" undertaken in
connection with the marketing of the offering of the Shares, including, without
limitation, expenses associated with the production of road show slides and
graphics, fees and expenses of any consultants engaged in connection with the
road show presentations with the prior approval of the Company, travel and
lodging expenses of the representatives and officers of the Company and any such
consultants, and the Company's proportionate cost of any aircraft chartered in
connection with the road show, (ix) all expenses in connection with any offer
and sale of the Shares outside of the United States, including filing fees and
the reasonable fees and disbursements of counsel for the Underwriters in
connection with offers and sales outside of the United States, (x) all
reasonable fees and disbursements of counsel incurred by the Underwriters in
connection with the Directed Share Program and stamp duties, similar taxes or
duties or other taxes, if any, incurred by the Underwriters in connection with
the Directed Share Program, and (xi) all other costs and expenses incident to
the performance of the obligations of the Company hereunder for which provision
is not otherwise made in this Section. It is understood, however, that except as
provided in this Section, Section 8 entitled "Indemnity and Contribution,"

                                                                            -12-



and the last paragraph of Section 11 below, the Underwriters will pay all of
their costs and expenses, including fees and disbursements of their counsel and
any advertising expenses connected with any offers they may make.

     The provisions of this Section shall not supersede or otherwise affect any
agreement that the Sellers may otherwise have for the allocation of such
expenses among themselves.

     8.    Indemnity and Contribution.

           8.1   Indemnification of the Underwriters by the Company. The Company
agrees to indemnify and hold harmless each Underwriter and each person, if any,
who controls any Underwriter within the meaning of either Section 15 of the
Securities Act or Section 20 of the Exchange Act, from and against any and all
losses, claims, damages and liabilities (including, without limitation, any
legal or other expenses reasonably incurred in connection with defending or
investigating any such action or claim) caused by any untrue statement or
alleged untrue statement of a material fact contained in the Registration
Statement or any amendment thereof, any preliminary prospectus or the Prospectus
(as amended or supplemented if the Company shall have furnished any amendments
or supplements thereto), or caused by any omission or alleged omission to state
therein a material fact required to be stated therein or necessary to make the
statements therein not misleading, except (i) insofar as such losses, claims,
damages or liabilities are caused by any such untrue statement or omission or
alleged untrue statement or omission based upon information relating to any
Underwriter furnished to the Company in writing by such Underwriter through you
expressly for use therein and (ii) that with respect to any preliminary
prospectus, the foregoing indemnity agreement shall not inure to the benefit of
any Underwriter from whom the person asserting any loss, claim, damage or
liability purchased Shares, or any person controlling such Underwriter, if
copies of the Prospectus were timely delivered to the Underwriter pursuant to
Section 5 and a copy of the Prospectus (as then amended or supplemented if the
Company shall have furnished any amendments or supplements thereto) was not sent
or given by or on behalf of such Underwriter to such person, if required by law
so to have been delivered, at or prior to the written confirmation of the sale
of the Shares to such person, and if the Prospectus (as so amended or
supplemented) would have cured the defect giving rise to such loss, claim,
damage, liability or expense.

           8.2   Indemnification of Company by the Selling Stockholders. Each
Selling Stockholder agrees, severally and not jointly, to indemnify and hold
harmless the Company, its directors, its officers who sign the Registration
Statement and each person, if any, who controls the Company within the meaning
of either Section 15 of the Securities Act or Section 20 of the Exchange Act,
from and against any and all losses, claims, damages and liabilities (including,
without limitation, any legal or other expenses reasonably incurred in
connection with defending or investigating any such action or claim) caused by
any untrue statement or alleged untrue statement of a material fact contained in
the Registration Statement or any amendment thereof, any preliminary prospectus
or the Prospectus (as amended or supplemented if the Company shall have
furnished any amendments or supplements thereto), or caused by any omission or
alleged omission to state therein a material fact required to be stated therein
or necessary to make the statements therein not misleading, but only with
reference to information relating to such Selling Stockholder furnished in
writing by or on behalf of such Selling Stockholder expressly for use in the
Registration Statement, any preliminary prospectus, the Prospectus or any
amendments or supplements thereto.

           8.3   Indemnification of Underwriters by Selling Stockholders.

                 (a) Each Selling Stockholder agrees, severally and not jointly,
to indemnify and hold harmless each Underwriter and each person, if any, who
controls any Underwriter within the meaning of either Section 15 of the
Securities Act or Section 20 of the Exchange Act, from and against any and all
losses, claims, damages and liabilities (including, without limitation, any
legal or other expenses reasonably incurred

                                                                            -13-



in connection with defending or investigating any such action or claim) caused
by any untrue statement or alleged untrue statement of a material fact contained
in the Registration Statement or any amendment thereof, any preliminary
prospectus or the Prospectus (as amended or supplemented if the Company shall
have furnished any amendments or supplements thereto), or caused by any omission
or alleged omission to state therein a material fact required to be stated
therein or necessary to make the statements therein not misleading, but only
with reference to information relating to such Selling Stockholder furnished in
writing by or on behalf of such Selling Stockholder expressly for use in the
Registration Statement, any preliminary prospectus, the Prospectus or any
amendments or supplements thereto.

                 (b) In the event that any Underwriter or any person, if any,
who controls any Underwriter within the meaning of either Section 15 of the
Securities Act or Section 20 of the Exchange Act shall have properly made any
request for indemnification pursuant to Section 8.1 and the Company (i) shall
have failed to pay such amount or otherwise failed to satisfy its obligations
set forth in Section 8.1 within 30 days of such request, or (ii) shall be, in
such indemnified party's reasonable judgment, unable or unwilling to satisfy
such obligations, each Selling Officer shall, severally and not jointly,
promptly indemnify and hold harmless such indemnified party to the same extent
as the Company shall be required to indemnify such indemnified party, or shall
contribute to the amount paid or payable by such indemnified party to the same
extent as the Company shall be required to contribute to such amount in the
event indemnification is unavailable or is insufficient as contemplated by
Section 8.8 or 8.9.

           8.4   Indemnification by the Underwriters. Each Underwriter agrees,
severally and not jointly, to indemnify and hold harmless the Company, the
Selling Stockholders, the directors of the Company, the officers of the Company
who sign the Registration Statement and each person, if any, who controls the
Company or any Selling Stockholder within the meaning of either Section 15 of
the Securities Act or Section 20 of the Exchange Act from and against any and
all losses, claims, damages and liabilities (including, without limitation, any
legal or other expenses reasonably incurred in connection with defending or
investigating any such action or claim) caused by any untrue statement or
alleged untrue statement of a material fact contained in the Registration
Statement or any amendment thereof, any preliminary prospectus or the Prospectus
(as amended or supplemented if the Company shall have furnished any amendments
or supplements thereto), or caused by any omission or alleged omission to state
therein a material fact required to be stated therein or necessary to make the
statements therein not misleading, but only with reference to information
relating to such Underwriter furnished to the Company in writing by such
Underwriter through you expressly for use in the Registration Statement, any
preliminary prospectus, the Prospectus or any amendments or supplements thereto.

           8.5   Indemnification Procedures. In case any proceeding (including
any governmental investigation) shall be instituted involving any person in
respect of which indemnity may be sought pursuant to this Section 8, such person
(the "indemnified party") shall promptly notify the person against whom such
indemnity may be sought (the "indemnifying party") in writing and the
indemnifying party, upon request of the indemnified party, shall retain counsel
reasonably satisfactory to the indemnified party to represent the indemnified
party and any others the indemnifying party may designate in such proceeding and
shall pay the fees and disbursements of such counsel related to such proceeding.
In any such proceeding, any indemnified party shall have the right to retain its
own counsel, but the fees and expenses of such counsel shall be at the expense
of such indemnified party unless (i) the indemnifying party and the indemnified
party shall have mutually agreed to the retention of such counsel or (ii) the
named parties to any such proceeding (including any impleaded parties) include
both the indemnifying party and the indemnified party and representation of both
parties by the same counsel would be inappropriate due to actual or potential
differing interests between them. It is understood that the indemnifying party
shall not, in respect of the legal expenses of any indemnified party in
connection with any proceeding or related proceedings in the same jurisdiction,
be liable for (i) the fees and expenses of more than one separate firm (in
addition to any local counsel) for all

                                                                            -14-



Underwriters and all persons, if any, who control any Underwriter within the
meaning of either Section 15 of the Securities Act or Section 20 of the Exchange
Act, (ii) the fees and expenses of more than one separate firm (in addition to
any local counsel) for the Company, its directors, its officers who sign the
Registration Statement and each person, if any, who controls the Company within
the meaning of either such Section and (iii) the fees and expenses of more than
one separate firm (in addition to any local counsel) for all Selling
Stockholders and all persons, if any, who control any Selling Stockholder within
the meaning of either such Section, and that all such fees and expenses shall be
reimbursed as they are incurred. In the case of any such separate firm for the
Underwriters and such control persons of any Underwriters, such firm shall be
designated in writing by Thomas Weisel Partners. In the case of any such
separate firm for the Company, and such directors, officers and control persons
of the Company, such firm shall be designated in writing by the Company. In the
case of any such separate firm for the Selling Stockholders and such control
persons of any Selling Stockholders, such firm shall be designated in writing by
the persons named as attorneys-in-fact for the Selling Stockholders under the
Powers of Attorney. The indemnifying party shall not be liable for any
settlement of any proceeding effected without its written consent, but if
settled with such consent or if there be a final judgment for the plaintiff, the
indemnifying party agrees to indemnify the indemnified party from and against
any loss or liability by reason of such settlement or judgment. Notwithstanding
the foregoing sentence, if at any time an indemnified party shall have requested
an indemnifying party to reimburse the indemnified party for fees and expenses
of counsel as contemplated by the second and third sentences of this paragraph,
the indemnifying party agrees that it shall be liable for any settlement of any
proceeding effected without its written consent if (i) such settlement is
entered into more than 60 days after receipt by such indemnifying party of the
aforesaid request and (ii) such indemnifying party shall not have reimbursed the
indemnified party in accordance with such request prior to the date of such
settlement. No indemnifying party shall, without the prior written consent of
the indemnified party, effect any settlement of any pending or threatened
proceeding in respect of which any indemnified party is or could have been a
party and indemnity could have been sought hereunder by such indemnified party,
unless such settlement includes an unconditional release of such indemnified
party from all liability on claims that are the subject matter of such
proceeding.

           8.6   Limitation of Selling Stockholder Liability. Notwithstanding
anything herein to the contrary, the liability of each Selling Stockholder under
the indemnity and contribution provisions of this Section 8 and the
representation in Section 2.9 shall be limited to an amount equal to the initial
public offering price of the Shares sold by such Selling Stockholder, less the
underwriting discount, as set forth on the front cover page of the Prospectus.
The Company and the Selling Stockholders may agree, as among themselves and
without limiting the rights of the Underwriters under this Agreement, as to the
respective amounts of such liability for which they each shall be responsible.

           8.7   Indemnification for Directed Share Program. The Company agrees
to indemnify and hold harmless Thomas Weisel Partners and each person, if any,
who controls Thomas Weisel Partners within the meaning of either Section 15 of
the Securities Act or Section 20 of the Exchange Act ("Thomas Weisel Partners
Entities"), from and against any and all losses, claims, damages and liabilities
(including, without limitation, any legal or other expenses reasonably incurred
in connection with defending or investigating any such action or claim) (i)
caused by any untrue statement or alleged untrue statement of a material fact
contained in the prospectus wrapper material prepared by or with the consent of
the Company for distribution in foreign jurisdictions in connection with the
Directed Share Program attached to the Prospectus or any preliminary prospectus,
or caused by any omission or alleged omission to state therein a material fact
required to be stated therein or necessary to make the statement therein, when
considered in conjunction with the Prospectus or any applicable preliminary
prospectus, not misleading; (ii) caused by the failure of any Participant to pay
for and accept delivery of the shares which, immediately following the
effectiveness of the Registration Statement, were subject to a properly
confirmed agreement to purchase; or (iii) related to, arising out of, or in
connection with the Directed Share Program, provided that, the Company shall not
be responsible

                                                                            -15-



 under this subparagraph (iii) for any losses, claim, damages or liabilities
(or expenses relating thereto) that are finally judicially determined to have
resulted from the bad faith or gross negligence of Thomas Weisel Partners
Entities.

           8.8   Contribution Agreement. To the extent the indemnification
provided for in this Section 8 is unavailable to an indemnified party or
insufficient in respect of any losses, claims, damages or liabilities referred
to therein, then each indemnifying party under such paragraph, in lieu of
indemnifying such indemnified party thereunder, shall contribute to the amount
paid or payable by such indemnified party as a result of such losses, claims,
damages or liabilities (i) in such proportion as is appropriate to reflect the
relative benefits received by the indemnifying party or parties on the one hand
and the indemnified party or parties on the other hand from the offering of the
Shares or (ii) if the allocation provided by clause 8(g) above is not permitted
by applicable law, in such proportion as is appropriate to reflect not only the
relative benefits referred to in Section 8.5 above but also the relative fault
of the indemnifying party or parties on the one hand and of the indemnified
party or parties on the other hand in connection with the statements or
omissions that resulted in such losses, claims, damages or liabilities, as well
as any other relevant equitable considerations. The relative benefits received
by the Sellers on the one hand and the Underwriters on the other hand in
connection with the offering of the Shares shall be deemed to be in the same
respective proportions as the net proceeds from the offering of the Shares
(before deducting expenses) received by each Seller and the total underwriting
discounts and commissions received by the Underwriters, in each case as set
forth in the table on the cover of the Prospectus, bear to the aggregate Public
Offering Price of the Shares. The relative fault of the Sellers on the one hand
and the Underwriters on the other hand shall be determined by reference to,
among other things, whether the untrue or alleged untrue statement of a material
fact or the omission or alleged omission to state a material fact relates to
information supplied by the Sellers or by the Underwriters and the parties'
relative intent, knowledge, access to information and opportunity to correct or
prevent such statement or omission. The Underwriters' respective obligations to
contribute pursuant to this Section 8 are several in proportion to the
respective number of Shares they have purchased hereunder, and not joint.

           8.9   Contribution Amounts. The Sellers and the Underwriters agree
that it would not be just or equitable if contribution pursuant to this Section
8 were determined by pro rata allocation (even if the Underwriters were treated
as one entity for such purpose) or by any other method of allocation that does
not take account of the equitable considerations referred to in Section 8.8. The
amount paid or payable by an indemnified party as a result of the losses,
claims, damages and liabilities referred to in the immediately preceding
paragraph shall be deemed to include, subject to the limitations set forth
above, any legal or other expenses reasonably incurred by such indemnified party
in connection with investigating or defending any such action or claim.
Notwithstanding the provisions of this Section 8, no Underwriter shall be
required to contribute any amount in excess of the amount by which the total
price at which the Shares underwritten by it and distributed to the public were
offered to the public exceeds the amount of any damages that such Underwriter
has otherwise been required to pay by reason of such untrue or alleged untrue
statement or omission or alleged omission. No person guilty of fraudulent
misrepresentation (within the meaning of Section 11(f) of the Securities Act)
shall be entitled to contribution from any person who was not guilty of such
fraudulent misrepresentation. The remedies provided for in this Section 8 are
not exclusive and shall not limit any rights or remedies which may otherwise be
available to any indemnified party at law or in equity; subject to the liability
limitations of the Selling Stockholders set forth in Section 8.6.

           8.10  Survival of Provisions. The indemnity and contribution
provisions contained in this Section 8 and the representations, warranties and
other statements of the Company and the Selling Stockholders contained in this
Agreement shall remain operative and in full force and effect regardless of (i)
any termination of this Agreement, (ii) any investigation made by or on behalf
of any Underwriter or any person controlling any Underwriter, any Selling
Stockholder or any person controlling any Selling

                                                                            -16-



Stockholder, or the Company, its officers or directors or any person controlling
the Company and (iii) acceptance of and payment for any of the Shares.

     9.    Effectiveness. This Agreement shall become effective upon the
execution and delivery hereof by the parties hereto.

     10.   Termination. This Agreement shall be subject to termination by notice
given by you to the Company, if (a) after the execution and delivery of this
Agreement and prior to the Closing Date (i) trading generally shall have been
suspended or materially limited on or by, as the case may be, any of the New
York Stock Exchange, the American Stock Exchange, the National Association of
Securities Dealers, Inc., the Chicago Board of Options Exchange, the Chicago
Mercantile Exchange or the Chicago Board of Trade, (ii) trading of any
securities of the Company shall have been suspended on any exchange or in any
over-the-counter market, (iii) a general moratorium on commercial banking
activities in New York, Delaware or California shall have been declared by
either federal or New York, Delaware or California state authorities or (iv)
there shall have occurred any outbreak or escalation of hostilities or any
change in financial markets or any calamity or crisis that, in your reasonable
judgment, is material and adverse, or (v) in the reasonable judgment of the
Representatives, there shall have occurred any material adverse change, or any
development that could reasonably be expected to result in a material adverse
change, in the condition, financial or otherwise, or in the earnings, business,
operations or prospects, whether or not arising from transactions in the
ordinary course of business, of the Company and its subsidiaries, taken as a
whole, and (b) in the case of any of the events specified in clauses 10(a)(i)
through 10(a)(v), such event, individually or together with any other such
event, makes it, in your reasonable judgment, impracticable to market the Shares
on the terms and in the manner contemplated in the Prospectus.

     11.   Defaulting Underwriters. If, on the Closing Date or the Option
Closing Date, as the case may be, any one or more of the Underwriters shall fail
or refuse to purchase Shares that it has or they have agreed to purchase
hereunder on such date, and the aggregate number of Shares which such defaulting
Underwriter or Underwriters agreed but failed or refused to purchase is not more
than one-tenth of the aggregate number of the Shares to be purchased on such
date, the other Underwriters shall be obligated severally in the proportions
that the number of Firm Shares set forth opposite their respective names in
Schedule A bears to the aggregate number of Firm Shares set forth opposite the
names of all such non-defaulting Underwriters, or in such other proportions as
you may specify, to purchase the Shares which such defaulting Underwriter or
Underwriters agreed but failed or refused to purchase on such date; provided
that in no event shall the number of Shares that any Underwriter has agreed to
purchase pursuant to this Agreement be increased pursuant to this Section 11 by
an amount in excess of one-ninth of such number of Shares without the written
consent of such Underwriter. If, on the Closing Date, any Underwriter or
Underwriters shall fail or refuse to purchase Firm Shares and the aggregate
number of Firm Shares with respect to which such default occurs is more than
one-tenth of the aggregate number of Firm Shares to be purchased, and
arrangements satisfactory to you, the Company and the Selling Stockholders for
the purchase of such Firm Shares are not made within 36 hours after such
default, this Agreement shall terminate without liability on the part of any
non-defaulting Underwriter, the Company or the Selling Stockholders. In any such
case either you or the relevant Sellers shall have the right to postpone the
Closing Date, but in no event for longer than seven (7) days, in order that the
required changes, if any, in the Registration Statement and in the Prospectus or
in any other documents or arrangements may be effected. If, on the Option
Closing Date, any Underwriter or Underwriters shall fail or refuse to purchase
Additional Shares and the aggregate number of Additional Shares with respect to
which such default occurs is more than one-tenth of the aggregate number of
Additional Shares to be purchased, the non-defaulting Underwriters shall have
the option to (i) terminate their obligation hereunder to purchase Additional
Shares or (ii) purchase not less than the number of Additional Shares that such
non-defaulting Underwriters would have been obligated to purchase in the absence
of such default. Any action taken under

                                                                            -17-



this paragraph shall not relieve any defaulting Underwriter from liability in
respect of any default of such Underwriter under this Agreement.

     If this Agreement shall be terminated by the Underwriters, or any of them,
because of any failure or refusal on the part of any Seller to comply with the
terms or to fulfill any of the conditions of this Agreement, or if for any
reason any Seller shall be unable to perform its obligations under this
Agreement, the Sellers will reimburse the Underwriters or such Underwriters as
have so terminated this Agreement with respect to themselves, severally, for all
out-of-pocket expenses (including the fees and disbursements of their counsel)
reasonably incurred by such Underwriters in connection with this Agreement or
the offering contemplated hereunder.

     12.   Counterparts. This Agreement may be signed in counterparts, each of
which shall be an original, with the same effect as if the signatures thereto
and hereto were upon the same instrument.

     13.   Headings; Table of Contents. The headings of the sections of this
Agreement and the table of contents have been inserted for convenience of
reference only and shall not be deemed a part of this Agreement.

     14.   Notices. All communications hereunder shall be in writing and shall
be mailed, hand delivered or telecopied and confirmed to the parties hereto as
follows:

           If to the Representatives:

           Thomas Weisel Partners LLC
           One Montgomery Street, Suite 3700
           San Francisco, California 94104
           Facsimile: (212) 271-3748
           Attention: James Streator

           with a copy to:

           Thomas Weisel Partners LLC
           One Montgomery Street, Suite 3700
           San Francisco, California 94104
           Facsimile: (415) 364-2694
           Attention: David A. Baylor, Esq.

           If to the Company:

           IMPAC Medical Systems, Inc.
           100 West Evelyn Avenue
           Mountain View, California 94041
           Facsimile:  650-623-8915
           Attention:  Joseph Jachinowski

           with a copy to:
           Orrick, Herrington & Sutcliffe LLP
           400 Sansome Street
           San Francisco, California 94111
           Facsimile: (415) 773-5759

                                                                            -18-



               Attention:  Alan Talkington, Esq.

               If to the Selling Stockholders:

               [Custodian]
               [address]
               Facsimile:  [___________]
               Attention:  [___________]

               with copies to:

               Orrick, Herrington & Sutcliffe LLP
               400 Sansome Street
               San Francisco, California 94111
               Facsimile:  (415) 773-5759
               Attention:  Alan Talkington, Esq.; and

               [Summit's Counsel]

               [address]
               Facsimile:  [___________]
               Attention:  [___________]

     Any party hereto may change the address for receipt of communications by
giving written notice to the others.

     15.   Successors. This Agreement will inure to the benefit of and be
binding upon the parties hereto, including any substitute Underwriters pursuant
to Section 11 hereof, and to the benefit of the officers and directors and
controlling persons referred to in Section 8, and in each case their respective
successors, and no other person will have any right or obligation hereunder. The
term "successors" shall not include any purchaser of the Shares as such from any
of the Underwriters merely by reason of such purchase.

     16.   Partial Unenforceability. The invalidity or unenforceability of any
Section, paragraph or provision of this Agreement shall not affect the validity
or enforceability of any other Section, paragraph or provision hereof. If any
Section, paragraph or provision of this Agreement is for any reason determined
to be invalid or unenforceable, there shall be deemed to be made such minor
changes (and only such minor changes) as are necessary to make it valid and
enforceable.

     17.   Governing Law. THIS AGREEMENT SHALL BE GOVERNED BY AND CONSTRUED IN
ACCORDANCE WITH THE INTERNAL LAWS OF THE STATE OF NEW YORK APPLICABLE TO
AGREEMENTS MADE AND TO BE PERFORMED IN SUCH STATE.

     18.   Consent to Jurisdiction. Any legal suit, action or proceeding arising
out of or based upon this Agreement or the transactions contemplated hereby
("Related Proceedings") may be instituted in the federal courts of the United
States of America located in the City and County of San Francisco or the courts
of the State of California in each case located in the City and County of San
Francisco (collectively, the "Specified Courts"), and each party irrevocably
submits to the exclusive jurisdiction (except for proceedings instituted in
regard to the enforcement of a judgment of any such court (a "Related
Judgment"), as to which such jurisdiction is non-exclusive) of such courts in
any such suit, action or proceeding. Service of any process, summons, notice or
document by mail to such party's address set forth above shall be effective
service of

                                                                            -19-



process for any suit, action or other proceeding brought in any such court. The
parties irrevocably and unconditionally waive any objection to the laying of
venue of any suit, action or other proceeding in the Specified Courts and
irrevocably and unconditionally waive and agree not to plead or claim in any
such court that any such suit, action or other proceeding brought in any such
court has been brought in an inconvenient forum.

     19.  Waiver of Immunity. With respect to any Related Proceeding, each party
irrevocably waives, to the fullest extent permitted by applicable law, all
immunity (whether on the basis of sovereignty or otherwise) from jurisdiction,
service of process, attachment (both before and after judgment) and execution to
which it might otherwise be entitled in the Specified Courts, and with respect
to any Related Judgment, each party waives any such immunity in the Specified
Courts or any other court of competent jurisdiction, and will not raise or claim
or cause to be pleaded any such immunity at or in respect of any such Related
Proceeding or Related Judgment, including, without limitation, any immunity
pursuant to the United States Foreign Sovereign Immunities Act of 1976, as
amended.

     20.  Failure of the Selling Stockholders to Sell and Deliver Shares. If one
or more of the Selling Stockholders shall fail to sell and deliver to the
Underwriters the Shares to be sold and delivered by such Selling Stockholders at
the Option Closing Date pursuant to this Agreement, then the Underwriters may at
their option, by written notice from the Representatives to the Company and the
Selling Stockholders, either (i) terminate this Agreement without any liability
on the part of any Underwriter or, except as provided in Sections 7 and 8
hereof, the Company or the Selling Stockholders, or (ii) purchase the shares
which the Company and other Selling Stockholders have agreed to sell and deliver
in accordance with the terms hereof. If one or more of the Selling Stockholders
shall fail to sell and deliver to the Underwriters the Shares to be sold and
delivered by such Selling Stockholders pursuant to this Agreement at the Option
Closing Date, then the Underwriters shall have the right, by written notice from
the Representatives to the Company and the Selling Stockholders, to postpone the
Option Closing Date, but in no event for longer than seven (7) days in order
that the required changes, if any, to the Registration Statement and the
Prospectus or any other documents or arrangements may be effected.

     21.  Entire Agreement. This Agreement constitutes the entire agreement of
the parties to this Agreement and supersedes all prior written or oral and all
contemporaneous oral agreements, understandings and negotiations with respect to
the subject matter hereof.

     22.  Amendments. This Agreement may only be amended or modified in writing,
signed by all of the parties hereto, and no condition herein (express or
implied) may be waived unless waived in writing by each party whom the condition
is meant to benefit.

     23.  Sophisticated Parties. Each of the parties hereto acknowledges that it
is a sophisticated business person who was adequately represented by counsel
during negotiations regarding the provisions hereof, including, without
limitation, the indemnification and contribution provisions of Section 8, and is
fully informed regarding said provisions. Each of the parties hereto further
acknowledges that the provisions of Section 8 hereto fairly allocate the risks
in light of the ability of the parties to investigate the Company, its affairs
and its business in order to assure that adequate disclosure has been made in
the Registration Statement, any preliminary prospectus and the Prospectus (and
any amendments and supplements thereto), as required by the Securities Act and
the Exchange Act.

                  [Remainder of page intentionally left blank]

                                                                            -20-



     If the foregoing is in accordance with your understanding of our agreement,
kindly sign and return to the Company the enclosed copies hereof, whereupon this
instrument, along with all counterparts hereof, shall become a binding agreement
in accordance with its terms.

                                    Very truly yours,

                                    IMPAC Medical Systems, Inc.


                                    By:_________________________________________
                                    Name: Joseph K. Jachinowski
                                    Title: President and Chief Executive Officer

                                    The Selling Stockholders
                                    named in Schedule B hereto,
                                    acting severally

                                    By:_________________________________________
                                         Attorney-in-Fact

Accepted as of the date hereof

Thomas Weisel Partners LLC
U.S. Bancorp Piper Jaffray
SG Cowen Securities Corporation

Acting severally on behalf
  of themselves and the
  several Underwriters named
  in Schedule A hereto.

By:   Thomas Weisel Partners LLC


By:__________________________________
Name:
Title:

                                                                            -21-




                                   SCHEDULE A

                                                                    Number of
              Underwriter                                          Firm Shares
                                                                 To Be Purchased

Thomas Weisel Partners LLC
U.S. Bancorp Piper Jaffray
SG Cowen Securities Corporation
[NAMES OF OTHER UNDERWRITERS]

                Total



                                   SCHEDULE B

                                                                    Number of
              Selling Stockholder                              Additional Shares
                                                                   To Be Sold

[NAMES OF SELLING SHAREHOLDERS]

                      Total



                                    EXHIBIT A

                    Form of Legal Opinion of Company Counsel

     i.     The Company has been duly incorporated, is validly existing as a
corporation in good standing under the laws of the State of Delaware, has the
corporate power and authority to own its property and to conduct its business as
described in the Prospectus and is duly qualified to transact business and is in
good standing in each jurisdiction in which the conduct of its business or its
ownership or leasing of property requires such qualification, except to the
extent that the failure to be so qualified or be in good standing would not have
a material adverse effect on the Company and its subsidiaries, taken as a whole.

     ii.    IMPAC Global Systems, Inc. has been duly incorporated, is validly
existing as a corporation in good standing under the laws of the State of
Delaware, has the corporate power and authority to own its property and to
conduct its business as described in the Prospectus and is duly qualified to
transact business and is in good standing in each jurisdiction in which the
conduct of its business or its ownership or leasing of property requires such
qualification, except to the extent that the failure to be so qualified or be in
good standing would not have a material adverse effect on the Company and its
subsidiaries, taken as a whole.

     iii.   All of the issued shares of capital stock of IMPAC Global Systems,
Inc. have been duly and validly authorized and issued, are fully paid and
non-assessable and are owned directly by the Company.

     iv.    The shares of Common Stock outstanding prior to the issuance of the
Shares to be sold by the Company have been duly authorized and are validly
issued, fully paid and non-assessable.

     v.     The Shares to be sold by the Company have been duly authorized and,
when issued and delivered in accordance with the terms of the Underwriting
Agreement, will be validly issued, fully paid and non-assessable, and, to such
counsel's knowledge, the issuance of such Shares will not be subject to any
preemptive or similar rights.

     vi.    The Underwriting Agreement has been duly authorized, executed and
delivered by the Company.

     vii.   The execution and delivery by the Company of, and the performance by
the Company of its obligations under, the Underwriting Agreement will not
contravene any provision of applicable law or the certificate of incorporation
or by-laws of the Company or, to the best of such counsel's knowledge, any
agreement or other instrument binding upon the Company or any of its
subsidiaries that that has been filed as an exhibit to the Registration
Statement, or, to the best of such counsel's knowledge, any judgment, order or
decree of any governmental body, agency or court having jurisdiction over the
Company or any subsidiary, and no consent, approval, authorization or order of,
or qualification with, any governmental body or agency is required for the
performance by the Company of its obligations under this Agreement, except such
as (a) have been obtained under the Securities Act, (b) may be required by the
securities or Blue Sky laws of the various states in connection with the offer
and sale of the Shares or (c) may be required by the NASD, in each case as to
which such counsel need express no opinion.

     viii.  The statements (A) in the Prospectus under the captions
"Management--Stock Plans," "Management--Indemnification," "Description of
Capital Stock" and "Underwriting" and (B) in the Registration Statement in Items
14 and 15, in each case insofar as such statements constitute summaries of the
legal matters, documents or proceedings referred to therein, fairly present the
information called for with respect to such legal matters, documents and
proceedings and fairly summarize the matters referred to therein.



     ix.  To such counsel's knowledge, there are no (A) legal or governmental
proceedings pending or threatened to which the Company or any of its
subsidiaries is a party or to which any of the properties of the Company or any
of its subsidiaries is subject that are required to be described in the
Registration Statement or the Prospectus and are not so described, or (B) any
statutes, regulations, contracts or other documents that are required to be
described in the Registration Statement or the Prospectus or to be filed as
exhibits to the Registration Statement that are not described or filed as
required (except as to regulatory matters as to which such counsel need not
express any opinion).

     x.   The Company is not and, after giving effect to the offering and sale
of the Shares and the application of the proceeds thereof as described in the
Prospectus, will not be an "investment company" as such term is defined in the
Investment Company Act of 1940, as amended.

     xi.  The Registration Statement and Prospectus (except for financial
statements and schedules and other financial and statistical data included
therein as to which such counsel need not express any opinion) comply as to form
in all material respects with the Securities Act and the applicable rules and
regulations of the Commission thereunder.

     In connection with the preparation of the Registration Statement and the
Prospectus, such counsel has participated in conferences with officers and other
representatives of the Company and with its certified public accountants, as
well as with representatives of the Underwriters and their counsel. At such
conferences, the contents of the Registration Statement and the Prospectus and
related matters were discussed. Such counsel has not independently verified and
accordingly is not confirming and assumes no responsibility for the accuracy or
completeness of the statements contained in the Registration Statement or the
Prospectus. On the basis of the foregoing, nothing has come to such counsel's
attention that has caused such counsel to believe (i) that the Registration
Statement (except as to the financial statements and schedules, related notes
and other financial data and statistical data derived therefrom, as to which
counsel need not express any belief) at the Effective Date contained any untrue
statement of a material fact or omitted to state a material fact required to be
stated therein or necessary to make the statements therein, in light of the
circumstances under which they were made, not misleading, or (ii) that the
Prospectus (except as to the financial statements and schedules, related notes
and other financial data and statistical data derived therefrom, as to which
counsel need not express any belief) as of its date or at the Closing Date,
contained or contains any untrue statement of a material fact or omitted or
omits to state a material fact necessary, in order to make the statements
therein, in light of the circumstances under which they were made, not
misleading.

                                                                             -2-



                                    EXHIBIT B

              Form of Legal Opinion of Selling Stockholders Counsel

     i.    The Underwriting Agreement has been duly authorized, executed and
delivered by or on behalf of each of the Selling Stockholders.

     ii.   The execution and delivery by each Selling Stockholder of, and the
performance by such Selling Stockholder of its obligations under, the
Underwriting Agreement and the Custody Agreement and Powers of Attorney of such
Selling Stockholder will not contravene any provision of applicable law, or the
[certificate] of incorporation or by-laws of such Selling Stockholder (if such
Selling Stockholder is a corporation), or, to such counsel's knowledge, any
agreement or other instrument binding upon such Selling Stockholder or, to such
counsel's knowledge, any judgment, order or decree of any governmental body,
agency or court having jurisdiction over such Selling Stockholder, and no
consent, approval, authorization or order of, or qualification with, any
governmental body or agency is required for the performance by such Selling
Stockholder of its obligations under the Underwriting Agreement or the Custody
Agreement or Power of Attorney of such Selling Stockholder, except such as (a)
have been obtained under the Securities Act, (b) may be required by the
securities or Blue Sky laws of the various states in connection with the offer
and sale of the Shares or (c) may be required by the NASD, in each case as to
which such counsel need express no opinion.

     iii.  The Custody Agreement and the Power of Attorney of each Selling
Stockholder have been duly authorized, executed and delivered by such Selling
Stockholder and are valid and binding agreements of such Selling Stockholder.

     Such counsel may rely with respect to factual matters and to the extent
such counsel deems appropriate, upon the representations of each Selling
Stockholder contained in the Underwriting Agreement and in the Custody Agreement
and Power of Attorney of such Selling Stockholder and in other documents and
instruments; provided that copies of such Custody Agreements and Powers of
Attorney and of any such other documents and instruments shall be delivered to
counsel to the Underwriters and shall be in form and substance satisfactory to
counsel to the Underwriters.



                                    EXHIBIT C

                            FORM OF LOCK-UP AGREEMENT

                                                                     May 9, 2002
Thomas Weisel Partners LLC
U.S. Bancorp Piper Jaffray
SG Cowen Securities Corporation
as Representatives of the several Underwriters
c/o Thomas Weisel Partners LLC
One Montgomery Street, Suite 3700
San Francisco, California 94104

                     Re: Lock-Up Agreement (the "Agreement")

Ladies and Gentlemen:

     The undersigned is an owner of record or beneficially of certain shares of
Common Stock, par value $0.0001 per share (the "Common Stock"), of IMPAC Medical
Systems, Inc., a California corporation (the "Company"), or securities
convertible into or exchangeable or exercisable for Common Stock. The
undersigned understands that you, as representatives (the "Representatives"),
propose to enter into an Underwriting Agreement on behalf of the several
Underwriters named in Schedule A to such agreement (collectively, the
"Underwriters"), with the Company providing for a public offering of the Common
Stock of the Company pursuant to a Registration Statement on Form S-1 to be
filed with the Securities and Exchange Commission (the "Public Offering"). The
undersigned recognizes that the Public Offering will be of benefit to the
undersigned and will benefit the Company by, among other things, raising
additional capital for its operations. The undersigned acknowledges that you and
the other Underwriters are relying on the representations and agreements of the
undersigned contained in this letter in carrying out the Public Offering and in
entering into underwriting arrangements with the Company with respect to the
Public Offering.

     To induce the Underwriters that may participate in the Public Offering to
continue their efforts in connection with the Public Offering, the undersigned
hereby agrees that, without the prior written consent of Thomas Weisel Partners
(which consent may be withheld in its sole discretion), it will not, during the
period commencing on the date hereof and ending 180 days after the date of the
final prospectus relating to the Public Offering (the "Prospectus"), (1) offer,
pledge, sell, contract to sell, sell any option or contract to purchase,
purchase any option or contract to sell, grant any option, right or warrant to
purchase, lend, or otherwise transfer or dispose of, directly or indirectly, any
shares of Common Stock or any securities convertible into or exercisable or
exchangeable for Common Stock, or (2) enter into any swap or other arrangement
that transfers to another, in whole or in part, any of the economic consequences
of ownership of the Common Stock, whether any such transaction described in
clause (1) or (2) above is to be settled by delivery of Common Stock or such
other securities, in cash or otherwise. In addition, the undersigned agrees
that, without the prior written consent of Thomas Weisel Partners (which consent
may be withheld in its sole discretion), it will not, during the period
commencing on the date hereof and ending 180 days after the date of the
Prospectus, make any demand for or exercise any right with respect to, the
registration of any shares of Common Stock or any security convertible into or
exercisable or exchangeable for Common Stock. With respect to the Public
Offering, the undersigned waives any registration rights relating to
registration under the Securities Act of any Common Stock owned either of record
or beneficially by the undersigned, including any rights to receive notice of
the Public Offering.



     The foregoing restrictions are expressly agreed to preclude the undersigned
from engaging in any hedging or other transaction that is designed to or
reasonably expected to lead to or result in a sale or disposition of the Common
Stock even if such Common Stock would be disposed of by someone other than the
undersigned. Such prohibited hedging or other transactions would include without
limitation any short sale or any purchase, sale or grant of any right (including
without limitation any put option or put equivalent position or call option or
call equivalent position) with respect to any of the Common Stock or with
respect to any security that includes, relates to, or derives any significant
part of its value from such Common Stock.

     Notwithstanding the foregoing, the undersigned may transfer shares of
Common Stock (i) as a bona fide gift or gifts, provided that the donee or donees
thereof agree to be bound by the restrictions set forth herein, (ii) to any
trust for the direct or indirect benefit of the undersigned or the immediate
family of the undersigned, provided that the trustee of the trust agrees to be
bound by the restrictions set forth herein, and provided further that any such
transfer shall not involve a disposition for value, (iii) to the Underwriters
pursuant to the Underwriting Agreement, or (iv) in transactions relating to
shares of Common Stock acquired by the undersigned in open market transactions
after the completion of the Public Offering. For purposes of this Agreement,
"immediate family" shall mean any relationship by blood, marriage or adoption,
not more remote than first cousin. In addition, notwithstanding the foregoing,
if the undersigned is a corporation, the corporation may transfer the capital
stock of the Company to any wholly-owned subsidiary of such corporation;
provided, however, that in any such case, it shall be a condition to the
transfer that the transferee execute an agreement stating that the transferee is
receiving and holding such capital stock subject to the provisions of this
Agreement and there shall be no further transfer of such capital stock except in
accordance with this Agreement, and provided further that any such transfer
shall not involve a disposition for value.

     The undersigned understands that whether or not the Public Offering
actually occurs depends on a number of factors, including stock market
conditions. The Public Offering will only be made pursuant to an Underwriting
Agreement, the terms of which are subject to negotiation among the Company and
the Underwriters.

     The undersigned agrees and consents to the entry of stop transfer
instructions with the Company's transfer agent and registrar against the
transfer of shares of Common Stock or securities convertible into or
exchangeable or exercisable for Common Stock held by the undersigned except in
compliance with the foregoing restrictions.

     This Agreement is irrevocable and will be binding on the undersigned and
the respective successors, heirs, personal representatives, and assigns of the
undersigned.

                                   Very truly yours,


                                   _____________________________________________
                                   (Signature)


                                   _____________________________________________
                                  (Print Name)


                                   _____________________________________________
                                   (Address)

                                                                             -2-