Document:

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                                                                    EXHIBIT 10.6

                         OIL STATES INTERNATIONAL, INC.

                           DEFERRED COMPENSATION PLAN

                           EFFECTIVE: NOVEMBER 1, 2003

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                                TABLE OF CONTENTS

<TABLE>
<CAPTION>
                      ARTICLE                                              PAGE
                      -------                                              ----
<S>                                                                       <C>
I    -   Definitions and Construction                                        I-1

II   -   Participation                                                      II-1

III  -   Account Credits and Allocations of Income or Loss                  II-1

IV   -   Deemed Investment of Funds                                         IV-1

V    -   Vested Interests                                                    V-1

VI   -   In-Service Distributions                                           VI-1

VII  -   Termination Benefits                                              VII-1

VIII -   Administration of the Plan                                       VIII-1

IX   -   Administration of Funds                                            IX-1

X    -   Nature of the Plan                                                  X-1

XI   -   Miscellaneous                                                      XI-1
</TABLE>

                                       (i)
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                         OIL STATES INTERNATIONAL, INC.

                           DEFERRED COMPENSATION PLAN

                              W I T N E S S E T H :

         WHEREAS, OIL STATES INTERNATIONAL, INC. (the "Company") has adopted the
OIL STATES INTERNATIONAL, INC. DEFERRED COMPENSATION PLAN, hereinafter referred
to as the "PLAN," to provide its directors and certain of its employees with the
ability to electively defer, on a before-tax basis, compensation until the
termination of their employment relationship with the Company and its
Subsidiaries; and

         WHEREAS, the Plan provides that it may be amended by the Committee;

         NOW, THEREFORE, the Committee hereby amends the Plan, as set forth
herein, effective November 1, 2003.

                                      (ii)
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                                       I.

                          DEFINITIONS AND CONSTRUCTION

         1.1      DEFINITIONS. Where the following words and phrases appear in
the Plan, they shall have the respective meanings set forth below, unless their
context clearly indicates to the contrary.

(1)      ACCOUNT(s): A Member's Company Account and/or Deferral Account,
         including the amounts credited thereto.

(2)      ANNUAL RETAINER: The annual retainer payable in cash by the Company to
         a member of its Board.

(3)      BASE SALARY: The base rate of pay payable in cash by the Company to or
         for the benefit of a Member who is an employee of the Company for
         services rendered while a Member.

(4)      CHANGE OF CONTROL: A "change of control" within the meaning of such
         term as defined in The 2001 Equity Participation Plan of Oil States
         International, Inc.

(5)      CODE: The Internal Revenue Code of 1986, as amended.

(6)      COMMITTEE: The administrative committee appointed by the Compensation
         Committee to administer the Plan.

(7)      COMMITTEE FEES: The cash fees payable to a Director for attending
         regular or special meetings of a committee of the Board of Directors of
         Oil States International, Inc.

(8)      COMPANY: Oil States International, Inc. and any Subsidiary which adopts
         the Plan pursuant to the provisions of Section 2.3.

(9)      COMPANY ACCOUNT: An individual account for each Member who is an
         employee to which is credited with the Company Deferrals made on his
         behalf pursuant to Section 3.2 and which is credited (or debited) for
         such account's allocation of net income (or net loss) as provided in
         Section 3.3.

(10)     COMPANY DEFERRALS: Deferrals made by the Company on a Member's behalf
         pursuant to Section 3.2.

(11)     COMPANY'S 401(k) PLAN: The Oil States International, Inc. Retirement
         Plan.

                                       I-1
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(12)     COMPENSATION: A Member's aggregate employee compensation or aggregate
         director fees from the Company, as applicable.

(13)     COMPENSATION COMMITTEE: The Compensation Committee of the Board of
         Directors of Oil States International, Inc.

(14)     DEFERRAL ACCOUNT: An individual account for each Member to which is
         credited his Compensation deferrals pursuant to Section 3.1 and which
         is credited (or debited) for such account's allocation of net income
         (or net loss) as provided in Section 3.3.

(15)     DIRECTOR: A member of the Board of Directors of Oil States
         International, Inc. who is not an employee of the Company or a
         Subsidiary.

(16)     ELECTION DATE: The first day of each Plan Year; provided, however, with
         respect to an individual who first becomes eligible to participate in
         the Plan after the beginning of a Plan Year, his Election Date shall be
         the 30th day following the date he is notified that he first became
         eligible or such shorter period as may be established by the Committee.

(17)     FUNDS: The investment funds designated from time to time for the deemed
         investment of Accounts pursuant to Article IV.

(18)     INCENTIVE PAY: Bonuses and other forms of incentive payments as
         determined from time to time by the Compensation Committee, that are
         payable in cash by the Company to or for the benefit of a Member for
         services rendered while a Member.

(19)     MEMBER: Each individual who has become a Member pursuant to Article II.

(20)     PLAN: The Oil States International, Inc. Deferred Compensation Plan, as
         amended from time to time.

(21)     PLAN YEAR: The calendar year.

(22)     SUBSIDIARY: Any corporation that is a "subsidiary corporation" of the
         Company within the meaning of section 424(f) of the Code and any other
         entity that would be such a "subsidiary corporation" if the entity were
         a corporation.

(23)     TRUST: The trust or agency relationship, if any, established under the
         Trust Agreement.

(24)     TRUST AGREEMENT: The trust or agency agreement, if any, entered into
         between the Company and the Trustee pursuant to Article X.

                                       I-2
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(25)     TRUST FUND: The funds and properties, if any, held pursuant to the
         provisions of the Trust Agreement, together with all income, profits
         and increments thereto.

(26)     TRUSTEE: The trustee(s) or agent(s), as the case may be, qualified and
         acting under the Trust Agreement at any time.

(27)     UNFORESEEABLE FINANCIAL EMERGENCY: An unexpected need of a Member for
         cash that (i) arises from a sudden and unexpected illness or accident
         of the Member or of a dependent of a Member, loss of the Member's
         property due to casualty, or similar extraordinary and unforeseeable
         circumstances arising as a result of events beyond the control of such
         Member and (ii) would result in severe financial hardship to such
         Member if his Compensation deferral election was not canceled pursuant
         to Section 3.1(c) and/or if a benefit payment pursuant to Section 6.1
         was not permitted. Cash needs arising from foreseeable events, such as
         the purchase of a house or education expenses for children, shall not
         be considered to be the result of an Unforeseeable Financial Emergency.
         Further, cash needs which may be relieved (a) through reimbursement or
         compensation by insurance or otherwise, or (b) by liquidation of the
         Member's assets, to the extent the liquidation of such assets would not
         itself cause severe financial hardship, or (c) by cessation of
         deferrals under the Plan shall not be considered to be Unforeseeable
         Financial Emergencies.

(28)     VALUATION DATES: Each business day on which the principal securities
         markets are open. For purposes of effecting all Plan transactions,
         e.g., withdrawals, distributions and investment fund changes, the
         Valuation Date for any such transaction shall be the date on which the
         assets of the Trust Fund allocated to the affected Account are debited
         or credited, as the case may be. If there is no Trust Fund, the
         applicable Valuation Date shall be the date determined by the
         Committee.

         1.2      NUMBER AND GENDER. Wherever appropriate herein, words used in
the singular shall be considered to include the plural and words used in the
plural shall be considered to include the singular. The masculine gender, where
appearing in the Plan, shall be deemed to include the feminine gender.

         1.3      HEADINGS. The headings of Articles and Sections herein are
included solely for convenience, and if there is any conflict between such
headings and the text of the Plan, the text shall control. The terms "Trust",
"Trustee", and "Trust Agreement" shall not be controlling as to the status of a
relationship or agreement being an agency or trust arrangement. Such terms are
used herein for descriptive convenience only.

                                       I-3
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                                       II.

                                  PARTICIPATION

         2.1      PARTICIPATION. Prior to each Election Date, the Committee, in
its sole discretion, shall select and notify those management or highly
compensated employees of the Company who shall be eligible to become Members as
of such Election Date. However, only employees who are members of a "select
group of management or highly compensated employees," within the meaning of
Section 201 of ERISA, shall be eligible to participate. Each Director shall
automatically be eligible to become a Member and shall be so notified by the
Committee prior to the Election Date. Each such eligible person may become a
Member on such Election Date by executing and filing with the Committee, prior
to such Election Date, the Compensation deferral election form prescribed by the
Committee for the Plan. Subject to the above ERISA requirements and the
provisions of Section 2.2, a Member shall remain eligible to defer Compensation
hereunder and receive an allocation of Company Deferrals, if any, for each Plan
Year following his initial year of participation in the Plan.

         2.2      CESSATION OF ACTIVE PARTICIPATION. Notwithstanding any
provision herein to the contrary, an individual who has become a Member of the
Plan, other than a Director, shall cease to be entitled to defer Compensation
hereunder or receive an allocation of Company Deferrals, if any, effective as of
any date designated by the Committee. Any such Committee action shall be
communicated to the affected individual prior to the effective date of such
action. Such an individual may again become entitled to defer Compensation
hereunder and receive an allocation of Company Deferrals, if any, beginning on
any subsequent Election Date selected by the Committee in its sole discretion.

         2.3      ADOPTING SUBSIDIARIES. It is contemplated that Subsidiaries of
the Company may adopt this Plan. Any Subsidiary, whether or not presently
existing, may become a party hereto by appropriate action of its officers and
the approval of the Committee, but without the need for approval of its board of
directors or of the Compensation Committee. The provisions of the Plan shall
apply equally to each Company and its employees in the same manner as is
expressly provided for Oil States International, Inc. and its employees, except
that the power to appoint or otherwise affect the Committee and the Trustee and
the power to amend or terminate the Plan or amend the Trust Agreement shall be
exercised by the Compensation Committee or Committee alone. Transfer of
employment among Companies and Subsidiaries shall not be considered a
termination of employment hereunder. Any Company may, by appropriate action of
its officers without the need for approval of its board of directors or the
Committee or the Compensation Committee, terminate its participation in the
Plan. Moreover, the Committee may, in its discretion, terminate a Company's
(other than Oil States International's) Plan participation at any time.

                                      II-1
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                                      III.

                ACCOUNT CREDITS AND ALLOCATIONS OF INCOME OR LOSS

         3.1      MEMBER DEFERRALS.

                  (a)      For any Plan Year (or applicable part thereof) a
Member may elect to defer any dollar amount (if an employee of the Company) or
an integral percentage, applied separately and respectively to each category of
Compensation as hereinafter specified, from 1% to 100% of his (i) Base Salary,
(ii) Incentive Pay, (iii) Annual Retainer and/or (iv) Committee Fees, as
applicable, less any required withholding taxes and payroll deductions elected
by the individual. Compensation for a Plan Year not so deferred by such election
shall be received by such Member in cash. If approved by the Committee, a
deferral election may provide for different levels of deferrals to be made at
different times during the year, or upon the occurrence of a specified date or
event during the year, "stair-stepped" elections, and different elections for
different forms of compensation. A Member's election to defer an amount of his
Compensation pursuant to this Section shall be made by executing a Compensation
deferral election form pursuant to which the Member authorizes the Company to
reduce his Compensation in the elected amount and the Company, in consideration
thereof, agrees to credit an equal amount to such Member's Deferral Account
maintained under the Plan. Compensation deferrals made by a Member shall be
credited to such Member's Deferral Account as of a date determined in accordance
with procedures established from time to time by the Committee; provided,
however, that such deferrals shall be credited to the Member's Deferral Account
no later than 30 days after the date upon which the Compensation deferred would
have been received by such Member in cash if he had not elected to defer such
amount pursuant to this Section 3.1. The reduction in a Member's Compensation
for a Plan Year pursuant to his Compensation deferral election shall be effected
by Compensation reductions within such Plan Year (or with respect to Incentive
Pay for a Plan Year, the date it is scheduled to be paid even if after the close
of such Plan Year) following the effective date of such election.

                  (b)      A Member's Compensation deferral election shall
become effective as of the Election Date which is on or after the election is
executed by the Member and filed with the Company. Except as provided below, a
Member's Compensation deferral election shall remain in force and effect for the
Plan Year which contains such Election Date and for all subsequent Plan Years
until changed by the Member by executing an election filed with the Company.

                  (c)      In the event that the Committee, upon written
petition of a Member, determines in its sole discretion that such Member has
suffered an Unforeseeable Financial Emergency or that such Member will, absent
termination of such Member's Compensation deferral election then in effect,
suffer an Unforeseeable Financial Emergency, then such Member's Compensation
deferral then in effect, if any, shall be terminated with respect to future
Compensation

                                      III-1
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as soon as administratively practicable after such determination. A Member whose
Compensation deferral election has been so terminated may again elect to defer a
portion of his Compensation, effective as of any subsequent Election Date that
is at least twelve months after the effective date of such termination, by
executing and delivering to the Company a new Compensation deferral election
prior to such Election Date.

                  (d)      Notwithstanding anything in this Plan to the
contrary, a Member who is an employee of the Employer must irrevocably elect, at
the time of making a deferral under this Plan for a Plan Year, either (i) to
have transferred to the Company's 401(k) Plan from his deferrals for such Plan
Year (but only from deferrals that the Member could have deferred directly to
the Company's 401(k) Plan) an amount equal to the lesser of (a) the maximum
amount that such Member could contribute to the Company's 401(k) Plan that Plan
Year as elective deferrals, subject to the limitations of Sections 401(k),
401(m), 402(g) and 415 of the Code and the terms of the Company's 401(k) Plan,
less any elective deferral contributions already made to the Company's 401(k)
Plan that Plan Year by the Member, or (b) the Member's deferrals under this Plan
for that Plan Year (but in either case without earnings, gains or losses
allocable thereto under this Plan) (the "401(k) Amount") or (ii) to have such
401(k) Amount returned to the Member in cash. Such transfer or return of the
401(k) Amount, as the case may be, shall be made within 2-1/2 months of the end
of the Plan Year or, if earlier, the Member's termination of employment. If a
Member fails to make the election required hereunder, he shall be deemed to have
irrevocably elected to transfer the 401(k) Amount to the Company's 401(k) Plan.
The Company shall be bound by a Member's election or deemed election.

         3.2      COMPANY DEFERRALS.

                  (a)      As of any date(s) selected by the Committee, the
Company may credit a Member's Company Account with such amount, if any, as the
Company shall determine in its sole discretion, including, without limitation,
matching contributions intended to make the Member "whole" had the Member
participated in the Company's 401(k) Plan and determined without regard to any
limitations on benefits under the Company's 401(k) Plan. Such credits may be
made on behalf of some Members but not others, and such credits may vary in
amount among individual Members.

                  (b)      Any Company matching contributions made under this
Plan with respect to the 401(k) Amount shall automatically be transferred (but
without earnings, gains or losses allocable thereto under this Plan) to the
Company's 401(k) Plan at the same time as the 401(k) Amount is transferred to
the Company's 401(k) Plan; provided, however, in no event shall the rate of such
transferred Company matching contributions exceed the matching rate under the
Company's 401(k) Plan, and the transfer of matching amounts shall be subject to
the terms of the Company's 401(k) Plan, including vesting and the limitations of
Sections 401(m) and 415 of the Code.

                                      III-2
<PAGE>

         3.3      ALLOCATION OF NET INCOME OR LOSS AND CHANGES IN VALUE AMONG
                  ACCOUNTS.

                  (a)      As of each Valuation Date, the Committee shall cause
to be determined the net income (or net loss) of each Fund for the period
elapsed since the next preceding Valuation Date. The net income (or net loss) of
each Fund since the next preceding Valuation Date shall be ascertained by the
Committee or its designee in such manner as it deems appropriate, provided that
such determination shall include any net increase or net decrease (whether or
not realized) in the value of the assets of each such Fund since the next
preceding Valuation Date, and may include expenses of administering the Fund,
the Trust and the Plan.

                  (b)      For purposes of allocations of net income (or net
loss), each Member's Accounts (or subaccounts) shall be divided into subaccounts
to reflect such Member's deemed investment designation in a particular Fund or
Funds pursuant to Article IV. As of each Valuation Date, the net income (or net
loss) of each Fund, separately and respectively, shall be allocated among the
corresponding subaccounts of the Members who had such corresponding subaccounts
on the next preceding Valuation Date, and each such corresponding subaccount
shall be credited with (or debited for) that portion of such net income (or net
loss) that the value of each such corresponding subaccount on such next
preceding Valuation Date was of the value of all such corresponding subaccounts
on such date; provided, however, that the value of such subaccounts as of the
next preceding Valuation Date shall be reduced by the amount of any payments
debited thereto in accordance with Section 7.4 since the next preceding
Valuation Date.

                  (c)      So long as there is any balance in any Account, such
Account shall continue to receive allocations pursuant to this Section.

                                      III-3
<PAGE>

                                       IV.

                           DEEMED INVESTMENT OF FUNDS

         Each Member shall designate, in accordance with the procedures
established from time to time by the Committee, the manner in which the amounts
allocated to his Accounts shall be deemed to be invested from among the Funds
made available from time to time for such purpose by the Committee. Such Member
may designate one of such Funds for the deemed investment of all the amounts
allocated to his Accounts or he may split the deemed investment of the amounts
allocated to his Accounts between such Funds in such increments as the Committee
may prescribe. If a Member fails to make a proper designation, then his Accounts
shall be deemed to be invested in the Fund or Funds designated by the Committee
from time to time in a uniform and nondiscriminatory manner.

         A Member may change his deemed investment designation for future
amounts to be allocated to his Accounts. Any such change shall be made in
accordance with the procedures established by the Committee, and the frequency
of such changes may be limited by the Committee.

         A Member may elect to convert his deemed investment designation with
respect to the amounts already allocated to his Accounts. Any such conversion
shall be made in accordance with the procedures established by the Committee,
and the availability and frequency of such conversions may be limited by the
Committee.

         Notwithstanding anything herein to the contrary, (i) at any time the
Committee may change the Funds made available for purposes of the Plan,
including "freezing" and deleting current Funds and (ii) if a phantom Company
stock fund is a Fund offered under the Plan, the Committee may impose such
restrictions on investments with respect to such Fund as the Committee deems
appropriate, including, without limitation, limitations on the frequency of
transfers, withdrawals, distributions, and pre-approvals of transactions with
respect to such Fund with the Company's securities compliance officer and in no
event may the 401(k) Amount be invested in the Company stock fund.

                                      IV-1
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                                       V.

                                VESTED INTERESTS

         5.1      ACCOUNTS. Except as otherwise provided below, a Member shall
have a 100% vested (nonforfeitable) interest in his Accounts at all times.

         Any Company matching deferrals made pursuant to Section 3.2(b) shall be
vested in accordance with the vesting schedule as in effect from time to time
under the Company's 401(k) Plan.

                                       V-1
<PAGE>

                                       VI.

                            IN-SERVICE DISTRIBUTIONS

         6.1      EMERGENCY BENEFIT. In the event that the Committee, upon
written petition of a Member, determines in its sole discretion that such Member
has suffered an Unforeseeable Financial Emergency, such Member shall be entitled
to a benefit in an amount not to exceed the lesser of (1) the amount determined
by the Committee as necessary to meet such Member's needs created by the
Unforeseeable Financial Emergency, or (2) the then value of such Member's
Accounts (other than amounts invested in the Company stock fund) as of the
applicable Valuation Date. Such benefit shall be paid in a single lump sum, cash
payment as soon as administratively practicable after the Committee has made its
determinations with respect to the availability and amount of such benefit. If a
Member's Accounts are deemed to be invested in more than one Fund, such benefit
shall be distributed pro rata from each Fund in which such Accounts are deemed
to be invested, but excluding the Company stock fund. No emergency withdrawal
shall be permitted from the Company stock fund.

         6.2      ELECTIVE WITHDRAWAL. A Member may elect at any time, by
effecting the election procedure prescribed by the Committee, to withdraw as a
benefit all, but not less than all, of the then value of such Member's Accounts
(other than amounts invested in the Company stock fund) as of the applicable
Valuation Date, subject to a withdrawal penalty of 10% of the then value of such
Member's Accounts as of such Valuation Date. Upon any such withdrawal, the
withdrawal penalty shall be forfeited to the Company. Any such withdrawal shall
be paid in a single lump sum, cash payment as soon as administratively
practicable. Upon any such withdrawal, such Member's participation in the Plan
shall terminate and no further deferrals shall be made under the Plan on behalf
of such Member. No elective withdrawal shall be permitted from the Company stock
fund.

         6.3      CHANGE OF CONTROL. Plan provisions to the contrary
notwithstanding, if there is a Change of Control, the Committee may, in its sole
discretion, fix a date, on or prior to the effective date of such Change of
Control, as of which the then value of the Members' Accounts may be paid in a
single lump sum payment as soon as administratively practicable.

         6.4      RESTRICTION ON IN-SERVICE DISTRIBUTIONS. This Article VI shall
not be applicable to a Member following his termination with the Company and its
Subsidiaries, and the amounts credited to such Member's Accounts shall be
payable to such Member in accordance with the provisions of Article VII.

                                      VI-1
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                                      VII.

                              TERMINATION BENEFITS

         7.1      AMOUNT OF BENEFIT. Upon a Member's termination with the
Company and all of its Subsidiaries for any reason, or, with respect to a Member
who is a Director, upon such Member ceasing to be a Director, the Member, or, in
the event of the death of the Member, the Member's designated beneficiary, shall
be entitled to a single lump sum payment of the then value of the Member's
Accounts as of the applicable Valuation Date or, if elected by the Member
pursuant to Section 7.5, shall be entitled to receive the value of the Member's
Accounts in installment payments as determined thereunder.

         7.2      TIME OF PAYMENT. Payment of a Member's benefit under Section
7.1 shall be made or begin as soon as administratively practicable after the
Valuation Date coincident with or next succeeding the termination date of the
Member. Notwithstanding the foregoing, no distribution shall be made from the
Company stock fund to a Member who would be subject to liability under Section
16(b) of the Securities Exchange Act of 1934, as amended, with respect to such
distribution until such time as the distribution would not result in such
liability.

         7.3      DESIGNATION OF BENEFICIARIES.

                  (a)      Each Member shall have the right to designate the
beneficiary or beneficiaries to receive payment of his benefit in the event of
his death. Each such designation shall be made by executing the beneficiary
designation form prescribed by the Committee and filing same with the Committee.
Any such designation may be changed at any time by execution of a new
designation in accordance with this Section.

                  (b)      If no such designation is on file with the Committee
at the time of the death of the Member or such designation is not effective for
any reason as determined by the Committee, then the designated beneficiary or
beneficiaries to receive such benefit shall be as follows:

                           (1)      If a Member leaves a surviving spouse, his
         benefit shall be paid to such surviving spouse; and

                           (2)      If a Member leaves no surviving spouse, his
         benefit shall be paid to such Member's executor or administrator, or to
         his heirs at law if there is no administration of such Member's estate.

         7.4      PAYMENT OF BENEFITS. To the extent the Trust Fund has
sufficient assets, the Trustee shall pay benefits to Members or their
beneficiaries, except to the extent the Company pays the

                                      VII-1
<PAGE>

benefits directly and provides adequate evidence of such payment to the Trustee.
To the extent the Trustee does not or cannot pay benefits out of the Trust Fund,
the benefits shall be paid by the Company. Any benefit payments made to a Member
or for his benefit pursuant to any provision of the Plan shall be debited to
such Member's Accounts. All benefit payments shall be made in cash to the
fullest extent practicable, other than amounts invested in the Company stock
fund which, if paid in a single lump sum payment, shall be distributed in cash
or in kind at the election of the Member.

         7.5      FORMS OF BENEFIT PAYMENTS.

                  (a)      All benefits shall be paid in one of the following
forms as elected by the Member:

                           (i)      a single lump sum payment; or

                           (ii)     in annual installment payments (e.g., 1/10,
         1/9, etc. of the balance of the Member's Accounts on the installment
         payment date) for a term certain not to exceed 10 years (as designated
         by the Member) beginning on the first of the month or as soon as
         reasonably practicable following his termination with the Company and
         on each anniversary of such month. In the event of such Member's death
         prior to the end of the designated installment term, any unpaid balance
         shall be paid in a lump sum to his designated beneficiary.

                  (b)      A Member may elect, on the form prescribed by the
Committee, one of the above forms of payment. Such election must be made not
later than one year prior to the date such Member terminates. An election shall
apply to all of the Member's Accounts. In the event a Member fails to elect the
form in which his benefit payments are to be made prior to such date, such
benefits shall be paid to such Member in the form of a single lump sum.

                  (c)      With the consent of the Committee, a Member may
change his elected form of benefit payment with respect to all of his Accounts,
provided, that, no such change shall be effective if made within 12 months of
the date such Member's employment terminates. A Member may make no more than 3
such election changes while participating in the Plan.

         7.6      CASH-OUT OF BENEFIT. The Committee, in its sole discretion,
may accelerate the payment of a terminated Member's Accounts at any time,
notwithstanding the form of benefit payment elected by the Member.

         7.7      UNCLAIMED BENEFITS. In the case of a benefit payable on behalf
of a Member, if the Committee is unable to locate the Member or beneficiary to
whom such benefit is payable, upon the Committee's determination thereof, such
benefit shall be forfeited to the Company. Notwithstanding the foregoing, if
subsequent to any such forfeiture the Member or beneficiary to whom such benefit

                                      VII-2
<PAGE>

is payable makes a valid claim for such benefit, such forfeited benefit shall be
restored to the Plan by the Company.

                                      VII-3
<PAGE>

                                      VIII.

                           ADMINISTRATION OF THE PLAN

         8.1      APPOINTMENT OF COMMITTEE. The general administration of the
Plan shall be vested in the Committee which shall be appointed by the
Compensation Committee and shall consist of one or more persons. Any individual,
whether or not an employee of the Company, is eligible to become a member of the
Committee.

         8.2      TERM, VACANCIES, RESIGNATION, AND REMOVAL. Each member of the
Committee shall serve until he resigns, dies, or is removed by the Compensation
Committee. At any time during his term of office, a member of the Committee may
resign by giving written notice to the Compensation Committee and the Committee,
such resignation to become effective upon the appointment of a substitute member
or, if earlier, the lapse of thirty days after such notice is given as herein
provided. At any time during his term of office, and for any reason, a member of
the Committee may be removed by the Compensation Committee with or without
cause, and the Compensation Committee may in its discretion fill any vacancy
that may result therefrom. Any member of the Committee who is an employee of the
Company shall automatically cease to be a member of the Committee as of the date
he ceases to be employed by the Company or any Subsidiary.

         8.3      SELF-INTEREST OF MEMBERS. No member of the Committee shall
have any right to vote or decide upon any matter relating solely to himself
under the Plan or to vote in any case in which his individual right to claim any
benefit under the Plan is particularly involved. In any case in which a
Committee member is so disqualified to act and the remaining members cannot
agree, the Compensation Committee shall appoint a temporary substitute member to
exercise all the powers of the disqualified member concerning the matter in
which he is disqualified.

         8.4      COMMITTEE POWERS AND DUTIES. The Committee shall supervise the
administration and enforcement of the Plan according to the terms and provisions
hereof and shall have all powers necessary to accomplish these purposes,
including, but not by way of limitation, the right, power, authority, and duty:

                  (a)      To make rules, regulations, and bylaws for the
         administration of the Plan that are not inconsistent with the terms and
         provisions hereof, and to enforce the terms of the Plan and the rules
         and regulations promulgated thereunder by the Committee;

                  (b)      To construe in its discretion all terms, provisions,
         conditions, and limitations of the Plan;

                                     VIII-1
<PAGE>

                  (c)      To correct any defect or to supply any omission or to
         reconcile any inconsistency that may appear in the Plan in such manner
         and to such extent as it shall deem in its discretion expedient to
         effectuate the purposes of the Plan;

                  (d)      To employ and compensate such accountants, attorneys,
         investment advisors, and other agents, employees, and independent
         contractors as the Committee may deem necessary or advisable for the
         proper and efficient administration of the Plan;

                  (e)      To determine in its discretion all questions relating
         to eligibility;

                  (f)      To determine whether and when there has been a
         termination of a Member's employment with the Company and its
         Subsidiaries;

                  (g)      To make a determination in its discretion as to the
         right of any person to a benefit under the Plan and to prescribe
         procedures to be followed by distributees in obtaining benefits
         hereunder;

                  (h)      To receive and review reports from the Trustee as to
         the financial condition of the Trust Fund, including its receipts and
         disbursements; and

                  (i)      To establish or designate Funds as investment options
         as provided in Article IV.

         8.5      CLAIMS REVIEW. In any case in which a claim for Plan benefits
of a Member or beneficiary is denied or modified, the Committee shall furnish
written notice to the claimant within ninety days (or within 180 days if
additional information requested by the Committee necessitates an extension of
the ninety-day period), which notice shall:

                  (a)      State the specific reason or reasons for the denial
         or modification;

                  (b)      Provide specific reference to pertinent Plan
         provisions on which the denial or modification is based;

                  (c)      Provide a description of any additional material or
         information necessary for the Member, his beneficiary, or
         representative to perfect the claim and an explanation of why such
         material or information is necessary; and

                  (d)      Explain the Plan's claim review procedure as
         contained herein.

In the event a claim for Plan benefits is denied or modified, if the Member, his
beneficiary, or a representative of such Member or beneficiary desires to have
such denial or modification reviewed,

                                     VIII-2
<PAGE>

he must, within sixty days following receipt of the notice of such denial or
modification, submit a written request for review by the Committee of its
initial decision. In connection with such request, the Member, his beneficiary,
or the representative of such Member or beneficiary may review any pertinent
documents upon which such denial or modification was based and may submit issues
and comments in writing. Within sixty days following such request for review the
Committee shall, after providing a full and fair review, render its final
decision in writing to the Member, his beneficiary or the representative of such
Member or beneficiary stating specific reasons for such decision and making
specific references to pertinent Plan provisions upon which the decision is
based. If special circumstances require an extension of such sixty-day period,
the Committee's decision shall be rendered as soon as possible, but not later
than 120 days after receipt of the request for review. If an extension of time
for review is required, written notice of the extension shall be furnished to
the Member, beneficiary, or the representative of such Member or beneficiary
prior to the commencement of the extension period.

         8.6      COMPANY TO SUPPLY INFORMATION. The Company shall supply full
and timely information to the Committee, including, but not limited to,
information relating to each Member's Compensation, termination of employment
and such other pertinent facts as the Committee may require. The Company shall
advise the Trustee of such of the foregoing facts as are deemed necessary for
the Trustee to carry out the Trustee's duties under the Plan and the Trust
Agreement. When making a determination in connection with the Plan, the
Committee shall be entitled to rely upon the aforesaid information furnished by
the Company.

         8.7      BINDING ARBITRATION. If, after fully utilizing the claims
review procedure set forth in Section 8.5 above, a controversy continues to
exist with respect to a claim for Plan benefits of a Member or beneficiary,
either the Member (or his beneficiary) or the Company shall submit the claim to
arbitration in accordance with the Employee Benefit Plan Claims Arbitration
Rules of the American Arbitration Association and judgment upon the award
rendered by the arbitrator may be entered in any court having jurisdiction
thereof. The arbitrator will not have the power to add to or ignore any
provisions of the Plan or applicable law. His decision shall not go beyond what
is necessary for interpretation and application of the Plan. The arbitrator
shall have the power to decide the claim upon motion of the parties, without
necessity of an oral arbitration hearing, if either party submits a motion
requesting a hearing on documents only.

         8.8      INDEMNITY. To the extent permitted by applicable law, the
Company shall indemnify and save harmless each member of the Committee and the
Compensation Committee against any and all expenses, liabilities and claims
(including legal fees incurred to defend against such liabilities and claims)
arising out of their discharge in good faith of responsibilities under or
incident to the Plan. Expenses and liabilities arising out of willful misconduct
shall not be covered under this indemnity. This indemnity shall not preclude
such further indemnities as may be available under insurance purchased by the
Company or provided by the Company under any bylaw, agreement, vote of

                                     VIII-3
<PAGE>

stockholders or disinterested directors or otherwise, as such indemnities are
permitted under applicable law.

                                     VIII-4
<PAGE>

                                       IX.

                             ADMINISTRATION OF FUNDS

         9.1      PAYMENT OF EXPENSES. All expenses incident to the
administration of the Plan and Trust, including but not limited to, legal,
accounting, Trustee fees, and expenses of the Committee, may be paid by the
Company and, if not paid by the Company, shall be paid by the Trustee from the
Trust Fund.

         9.2      TRUST FUND PROPERTY. All income, profits, recoveries,
contributions, forfeitures and any and all moneys, securities and properties of
any kind at any time received or held by the Trustee shall be held for
investment purposes as a commingled Trust Fund pursuant to the terms of the
Trust Agreement. The Committee shall maintain one or more Accounts in the name
of each Member, but the maintenance of an Account designated as the Account of a
Member shall not mean that such Member shall have a greater or lesser interest
than that due him by operation of the Plan and shall not be considered as
segregating any funds or property from any other funds or property contained in
the commingled fund. No Member shall have any title to any specific asset in the
Trust Fund.

                                      IX-1
<PAGE>

                                       X.

                               NATURE OF THE PLAN

         The Plan is intended to constitute an unfunded, unsecured plan of
deferred compensation for (i) the Directors and (ii) for a select group of
management or highly compensated employees of the Company. Plan benefits herein
provided are to be paid out of the Company's general assets. Nevertheless,
subject to the terms hereof and of the Trust Agreement, the Company may, in the
sole discretion of the Committee, transfer money or other property to the
Trustee and the Trustee shall pay Plan benefits to Members and their
beneficiaries out of the Trust Fund.

         The Company, in its sole discretion, may establish the Trust and enter
into the Trust Agreement. In such event, the Company shall remain the owner of
all assets in the Trust Fund and the assets shall be subject to the claims of
Company creditors if the Company ever becomes insolvent. For purposes hereof,
the Company shall be considered "insolvent" if (a) the Company is unable to pay
its debts as they become due, or (b) the Company is subject to a pending
proceeding as a debtor under the United States Bankruptcy Code (or any successor
federal statute). The chief executive officer of the Company and its board of
directors shall have the duty to inform the Trustee in writing if the Company
becomes insolvent. Such notice given under the preceding sentence by any party
shall satisfy all of the parties' duty to give notice. When so informed, the
Trustee shall suspend payments to the Members and hold the assets for the
benefit of the Company's general creditors. If the Trustee receives a written
allegation that the Company is insolvent, the Trustee shall suspend payments to
the Members and hold the Trust Fund for the benefit of the Company's general
creditors, and shall determine within the period specified in the Trust
Agreement whether the Company is insolvent. If the Trustee determines that the
Company is not insolvent, the Trustee shall resume payments to the Members. No
Member or beneficiary shall have any preferred claim to, or any beneficial
ownership interest in, any assets of the Trust Fund.

                                       X-1
<PAGE>

                                       XI.

                                  MISCELLANEOUS

         11.1     NOT CONTRACT OF EMPLOYMENT. The adoption and maintenance of
the Plan shall not be deemed to be a contract between the Company and any person
or to be consideration for the employment of any person. Nothing herein
contained shall be deemed to give any person the right to be retained in the
employ of the Company or to restrict the right of the Company to discharge any
person at any time nor shall the Plan be deemed to give the Company the right to
require any person to remain in the employ of the Company or to restrict any
person's right to terminate his employment at any time.

         11.2     ALIENATION OF INTEREST FORBIDDEN. The interest of a Member or
his beneficiary or beneficiaries hereunder may not be sold, transferred,
assigned, or encumbered in any manner, either voluntarily or involuntarily, and
any attempt so to anticipate, alienate, sell, transfer, assign, pledge,
encumber, or charge the same shall be null and void; neither shall the benefits
hereunder be liable for or subject to the debts, contracts, liabilities,
engagements or torts of any person to whom such benefits or funds are payable,
nor shall they be an asset in bankruptcy or subject to garnishment, attachment
or other legal or equitable proceedings.

         11.3     WITHHOLDING. All Compensation deferrals and payments provided
for hereunder shall be subject to applicable tax withholding and other
deductions as shall be required of the Company under any applicable law.

         11.4     AMENDMENT AND TERMINATION. The Compensation Committee may from
time to time, in its discretion, amend, in whole or in part, any or all of the
provisions of the Plan; provided, however, that no amendment may be made that
would materially impair the rights of a Member with respect to amounts already
allocated to his Accounts. The Committee may also similarly amend the Plan
provided that no such amendment may materially increase the obligations of the
Company hereunder. The Compensation Committee may terminate the Plan at any
time. In the event that the Plan is terminated, the balance in a Member's
Accounts shall be paid to such Member or his designated beneficiary in a single
lump sum, cash payment in full satisfaction of all of such Member's or
beneficiary's benefits hereunder.

         11.5     SEVERABILITY. If any provision of this Plan shall be held
illegal or invalid for any reason, said illegality or invalidity shall not
affect the remaining provisions hereof; instead, each provision shall be fully
severable and the Plan shall be construed and enforced as if said illegal or
invalid provision had never been included herein.

                                      XI-1
<PAGE>

         11.6     GOVERNING LAWS. ALL PROVISIONS OF THE PLAN SHALL BE CONSTRUED
IN ACCORDANCE WITH THE LAWS OF TEXAS (WITHOUT REGARD TO ANY CONFLICTS OF LAW
PRINCIPLES) EXCEPT TO THE EXTENT PREEMPTED BY APPLICABLE FEDERAL LAW.

         EXECUTED November 1, 2003, effective for all purposes as provided
above.

                                           OIL STATES INTERNATIONAL, INC.

                                           By:   /s/ Cindy Taylor
                                               ---------------------------------
                                               Name:  Cindy Taylor
                                               Title: Senior Vice President &
                                                      Chief  Financial Officer

                                           ADOPTING SUBSIDIARIES

                                           1. Oil States Industries, Inc.

                                           2. HWC Energy Services, Inc.

                                           3. General Marine Leasing, Inc.

                                           4. Sooner Inc.

                                      XI-2<PAGE>
                                                                     EXHIBIT 4.1

                          REGISTRATION RIGHTS AGREEMENT

THIS REGISTRATION RIGHTS AGREEMENT ("Agreement") is made and entered into as of
February 23, 2004, by and between Input/Output, Inc., a Delaware corporation
("I/O" or the "Company"), and the persons and entities listed on Annex A
attached hereto ("Stockholders"). I/O and each Stockholder is each a "party" and
together the "parties" to this Agreement.

                                    RECITALS

Sensor Nederland B.V., a company organized and existing under the laws of the
Netherlands and wholly-owned subsidiary of I/O ("Sensor"), and certain
stockholders of Concept Systems Holdings Limited, a private limited company
incorporated in Scotland ("Concept"), have entered into a Share Acquisition
Agreement dated as of February 23, 2004 ("Acquisition Agreement"), pursuant to
which Sensor has acquired the entire share capital of Concept.

As a result of the consummation of the transactions contemplated by the
Acquisition Agreement, the Stockholders currently own the number of shares (the
"Shares") of Common Stock (defined below) of the Company set forth on Annex A
attached hereto

         I/O wishes to grant the Stockholders certain registration rights in the
Shares.

         NOW, THEREFORE, in consideration of the mutual promises and covenants
that follow, the parties agree as follows:

1. CERTAIN DEFINITIONS. Terms used in this Agreement shall have the following
meanings:

                  "COMMISSION" means the Securities and Exchange Commission or
         any other federal agency at the time administering the Securities Act.

                  "COMMON STOCK" means I/O's common stock, par value $0.01 per
         share.

                  "REGISTRABLE SECURITIES" means (i) the Shares; and (ii) any
         shares of Common Stock issued or issuable at any time or from time to
         time in respect of the Shares upon a stock split, stock dividend,
         recapitalization or other similar event involving I/O; PROVIDED,
         HOWEVER, that shares of Common Stock which are Registrable Securities
         shall cease to be Registrable Securities upon any sale pursuant to a
         registration statement under the Securities Act, Section 4(1) of the
         Securities Act or Rule 144 under the Securities Act, or any sale in any
         manner to a person or entity which, by virtue of Section 3.2 of this
         Agreement, is not entitled to the rights provided by this Agreement.

                  The terms "REGISTER," "REGISTERED", and "REGISTRATION" refer
         to a registration effected by preparing and filing a registration
         statement in compliance with the Securities Act, and the declaration or
         ordering by the Commission of the effectiveness of such registration
         statement.

                                        1
<PAGE>

                  "REGISTRATION EXPENSES" means all (a) expenses, other than
         Selling Expenses (as defined below), incurred by I/O in complying with
         Section 2 of this Agreement, but excluding the compensation of regular
         employees of I/O which shall be paid in any event by I/O and (b) fees,
         disbursements and expenses (limited to an aggregate amount of up to
         $25,000 in legal fees for any one registration) of no more than one
         counsel for all of the Stockholders retained in connection with such
         registration.

                  "SECURITIES ACT" means the Securities Act of 1933, as amended,
         or any similar federal statute and the rules and regulations
         promulgated by the Commission, all as in effect at the time.

                  "SELLING EXPENSES" means only the underwriting discounts,
         selling commissions and stock transfer taxes applicable to the
         securities registered by the Stockholder and all fees and disbursements
         of counsel for the Stockholders, except as described in the definition
         of "Registration Expenses" above.

                  "STOCKHOLDERS" means those persons and entities listed in
         Annex A attached hereto and any transferee pursuant to the terms of
         Section 3.2; "STOCKHOLDER" means any such person, entity or transferee;
         provided, however, that any person, entity or transferee who does not
         hold Registrable Securities shall not be considered a "STOCKHOLDER" or
         one of the "STOCKHOLDERS" for the purposes of this Agreement.

                  "UNDERWRITTEN PUBLIC OFFERING" means a public offering in
         which the Common Stock is offered and sold on a firm commitment basis
         through one or more underwriters, all pursuant to an underwriting
         agreement to which I/O and the underwriters, among others, are parties.

2.       REGISTRATION RIGHTS.

         2.1      PIGGYBACK REGISTRATION.

                  (a) NOTICE OF REGISTRATION. If at any time during the term of
         this Agreement, I/O proposes to register any of its Common Stock for
         its own account or for the account of any other stockholders (including
         any Stockholder) relating to an Underwritten Public Offering, I/O
         shall:

                           (i) promptly, but in any event at least twenty (20)
                  days before I/O files a registration statement pursuant to an
                  Underwritten Public Offering, give to each Stockholder written
                  notice. Such notice shall specify, at a minimum, the number of
                  shares of Common Stock so proposed to be registered, the
                  proposed date of filing the registration statement, any
                  proposed means of distribution of the shares, and any proposed
                  managing underwriter of the shares; and

                           (ii) subject to Section 2.9 hereof, include in up to
                  two of such registrations (and any related blue sky laws
                  qualification) the Registrable Securities as the Stockholders
                  request in a writing or writings delivered to I/O

                                        2
<PAGE>

                  within (ten) 10 days after receipt of I/O's written notice
                  delivered pursuant to Section 2.1(a)(i) above. I/O shall have
                  no obligation to include in the registration any Registrable
                  Securities of the Stockholders from whom a written request was
                  not timely received. Notwithstanding the forgoing to the
                  contrary, in the event that the Stockholders request inclusion
                  of Registrable Securities in an Underwritten Public Offering
                  prepared by I/O for the account of another stockholder, I/O
                  shall only have the obligation to include such Registrable
                  Securities, if any, as I/O shall have the right (contractual
                  or otherwise) to include in such Underwritten Public Offering.

                  (b) RIGHT TO TERMINATE REGISTRATION. I/O shall have the right
         to terminate or withdraw any registration initiated by I/O under this
         Section 2.1 prior to the effectiveness of the registration whether the
         Stockholder has elected to include its Registrable Securities in the
         registration; PROVIDED, HOWEVER, that in such event, I/O shall promptly
         pay all reasonable out-of-pocket costs and expenses of the Stockholder
         incurred in connection with the terminated registration.

                  (c) AGREEMENT WITH UNDERWRITER. The right of a Stockholder to
         have its Registrable Securities included in an Underwritten Public
         Offering pursuant to this section 2.1 shall be conditioned upon the
         Stockholder's entering into an underwriting agreement (containing
         customary representations, warranties, indemnities and agreements) with
         the underwriter or underwriters selected for underwriting by the
         Company, to the extent such underwriter or underwriters require that
         participants in the Underwritten Public Offering enter into such
         underwriting agreement. If a Stockholder disapproves of the terms of
         any such underwriting agreement, it may elect to withdraw therefrom by
         delivering written notice to the Company. Any Registrable Securities so
         withdrawn shall be entitled to such registration rights granted to such
         Registrable Securities pursuant to Section 2.1 (or 2.2, as the case may
         be) as may thereafter remain in effect.

         2.2 DEMAND REGISTRATIONS. At any time during the term of this Agreement
after the earlier of (i) 60 days after the date hereof and (ii) the
effectiveness of the Company's registration statement on Form S-3 filed with the
Securities and Exchange Commission on January 27, 2004, the Stockholders may
make up to two written requests for registration under the Securities Act,
pursuant to this Section 2.2 of all or part of their Registrable Securities
(each a "Demand Registration"). Each such request will specify the number of
shares of Registrable Securities proposed to be sold and will also specify the
intended method of disposition thereof. Within five (5) days following receipt
of such request, the Company shall give written notice of such request to each
Stockholder. Any Stockholder may elect, by giving written notice thereof to the
Company within twenty (20) days following the receipt of such notice, to include
all or part of such Stockholder's Registrable Securities in the registration
statement for such Demand Registration. The Company shall not be required to
effect more than two Demand Registrations pursuant to this Section 2.2, and each
such Demand Registration shall not be made for less than 420,000 shares of
Registrable Securities; provided, however, that one of such Demand Registrations
may be made for less than 420,000 shares of Registrable Securities in the event
that there are less than 420,000 shares of Registrable Securities outstanding.
The Stockholders agree and acknowledge that I/O will only be obligated to
accommodate two Demand Registrations

                                        3
<PAGE>

under the terms of this Agreement, regardless of how many Stockholders
participate in one or both Demand Registrations. If a registration has become
effective but is withdrawn before completion of the offering contemplated
thereby, or if a registration statement has been withdrawn prior to becoming
effective, then such registration shall not count as either of the Demand
Registrations contemplated by this Section 2.2; provided, however, that if any
such withdrawal (including, without limitation, withdrawals pursuant to Section
2.6 hereof) is made at the request of Stockholders holding a majority of the
Registrable Securities requested to be included in the registration, then such
withdrawn registration shall count as a Demand Registration, unless the Holders
of Registrable Securities to be included in such registration reimburse the
Company for its Registration Expenses relating to the preparation and filing of
such Demand Registration; and provided, further, that if such withdrawal by the
Stockholders was due to a material adverse change in the business or financial
condition of the Company which the Stockholders became aware of after the
commencement of the Demand Registration, the Stockholders shall not be required
to reimburse the Company for its Registration Expenses relating to the
preparation and filing of such Demand Registration, and such registration shall
not count as either of the Demand Registrations contemplated by this Section
2.2. If the Company withdraws a registration statement under this Section 2.2
(other than at the request of the Stockholders holding a majority of the
Registrable Securities requested to be included in the registration), the
Company shall not, until after the registration of the Registrable Securities
that were included in such withdrawn Demand Registration and after the
expiration of the time periods set forth in Section 2.2(a), register any Common
Stock, other than on a registration statement on Form S-4 or Form S-8 (or any
equivalent registration form then in effect).

                  (a) UNDERWRITTEN PUBLIC OFFERING. If a Demand Registration is
         in the form of an underwritten offering, the Stockholders (pursuant to
         the election of Stockholders then holding a majority of the Registrable
         Securities) shall select the underwriter for such offering subject to
         the approval of the Company (which approval shall not be unreasonably
         withheld), and the Company shall enter into an underwriting agreement
         with such underwriter containing representations, warranties,
         indemnities and agreements then customarily included by an issuer in
         underwriting agreements with respect to secondary distributions.
         Subject to the second proviso set forth in Section 2.4(a) hereof, the
         Company shall not cause the registration under the Securities Act of
         any other shares of its Common Stock to become effective (other than
         registration of an employee stock plan, or registration in connection
         with any Rule 145 or similar transaction) after the Company receives a
         request for a Demand Registration and during the effectiveness of a
         registration requested hereunder for an underwritten public offering.

                  (b) INCLUSION OF ADDITIONAL SHARES. The Company may include in
         a registration pursuant to this Section 2.2 securities for its own
         account or for the account of other third parties (including officers
         and employees of the Company), in amounts as determined by the
         Company's Board of Directors ("Additional Shares") so long as the
         inclusion thereof does not in any way exclude or otherwise impair the
         rights of the Stockholders who have requested registration pursuant to
         Section 2.2 above to include in such registration all Registrable
         Securities so requested. Notwithstanding any other provision of this
         Agreement to the contrary, if the underwriter managing the offering
         determines that, because of marketing factors, all of the Registrable

                                        4
<PAGE>

         Securities and Additional Shares requested to be registered may not be
         included in the offering, then all or a portion of the Additional
         Shares shall be excluded to the extent so required by such limitation,
         prior to the exclusion, if any, of Registrable Securities of the
         Stockholders. To facilitate the allocation of shares in accordance with
         the above provisions, the Company or the underwriters may round the
         number of shares allocated to any person to the nearest 100 shares.

                  (c) LIMIT IN ANY TWELVE MONTH PERIOD. I/O shall not be
         required to effect any registration of Registrable Securities within 12
         months of the effectiveness of a prior registration of Registrable
         Securities effected pursuant to this Section 2.2 in which all
         Registrable Securities requested to be included therein in compliance
         with the terms of this Agreement were included and sold thereunder.

         2.3 EXPENSES OF REGISTRATION. Except as otherwise set forth in Section
2.2, all Registration Expenses incurred in connection with registrations
pursuant to Section 2.1 piggyback registrations or Section 2.2 demand
registrations shall be borne by I/O. All Selling Expenses relating to securities
registered on behalf of the Stockholders pursuant to Sections 2.1 and 2.2 shall
be borne by the Stockholders.

         2.4 I/O'S OBLIGATIONS IN REGISTRATION. Whenever the Stockholder has
requested that any Registrable Securities be registered pursuant to this
Agreement, the Company will use its reasonable best efforts to effect the
registration of such Registrable Securities under the Securities Act, as
provided herein, and as expeditiously as possible:

                  (a) prepare and file with the Commission as soon as
         practicable but in no event later than thirty (30) days after receipt
         of a request to file a registration statement (unless the Securities
         Act, the Commission, or rules promulgated by the Commission under the
         Securities Act require that the Company include information in a
         registration statement that is not then available, in which case the
         Company will file such registration statement when such requirements
         may be satisfied) with respect to Registrable Securities, a
         registration statement on any form for which the Company then qualifies
         or which counsel for the Company shall deem appropriate and which form
         shall be available for the sale of such issue of Registrable Securities
         in accordance with the intended method of distribution thereof, and use
         its reasonable best efforts to cause such registration statement to
         become effective as promptly as practicable thereafter; PROVIDED, that
         if the Company shall furnish to the Stockholders a certificate signed
         by the Chief Executive Officer of the Company stating that in the good
         faith reasonable judgment of the Board of Directors it would be
         significantly disadvantageous to the Company and its stockholders for
         such a registration statement to be filed on or before the date filing
         would be required or to become effective, the Company shall have an
         additional period of not more than sixty (60) days within which to file
         (or before which it requests the effectiveness of) such registration
         statement; and PROVIDED FURTHER, that if the Company postpones the
         filing of a registration statement, the Company shall not, during the
         period of postponement, register any Common Stock (other than on a
         registration statement on Form S-4 or Form S-8 or any equivalent
         registration form then in effect) unless the Stockholders are allowed
         to include their Registrable Securities in such registration of Common
         Stock (subject to the limitations imposed by Section 2.9

                                        5
<PAGE>

         hereof); and PROVIDED, FURTHER, that before filing a registration
         statement or prospectus or any amendments or supplements thereto, the
         Company will (i) furnish to counsel selected by each seller of
         Registrable Securities copies of all such documents proposed to be
         filed and (ii) notify each seller of Registrable Securities of any stop
         order issued or threatened by the Commission and take all actions
         required to prevent the entry of such stop order or to remove it if
         entered at the earliest practicable date;

                  (b) prepare and file with the Commission such amendments and
         supplements to such registration statement and the prospectus used in
         connection therewith as may be necessary to keep such registration
         statement effective (and such prospectus current as required by the
         Securities Act) for a period of not less than 90 days after the date of
         effectiveness or such shorter period which will terminate when all
         Registrable Securities covered by such registration statement have been
         sold (but not before the expiration of the applicable period referred
         to in Section 4(3) of the Securities Act and Rule 174 thereunder, if
         applicable), and comply with the provisions of the Securities Act with
         respect to the disposition of all securities covered by such
         registration statement during such period in accordance with the
         intended methods of disposition by the sellers thereof set forth in
         such registration statement;

                  (c) provide (i) the Stockholders to be included in the
         registration statement and (ii ) not more than one counsel for all the
         Stockholders, the opportunity to review any drafts of the registration
         statement, each prospectus included therein or filed with the
         Commission, and each amendment or supplement thereto, and comment
         thereon;

                  (d) furnish to each seller of Registrable Securities to be
         included in a registration statement copies of such registration
         statement as filed and each amendment and supplement thereto (in each
         case including all exhibits thereto), the prospectus included in such
         registration statement (including each preliminary prospectus) and each
         amendment and supplement thereto and such other documents as such
         seller may reasonably request in order to facilitate the disposition of
         the Registrable Securities owned by such seller;

                  (e) use its reasonable best efforts to register or qualify
         such Registrable Securities under such other securities or blue sky
         laws of such jurisdictions as any seller reasonably requests and do any
         and all other acts and things which may be necessary or advisable to
         enable such seller to consummate the disposition in such jurisdictions
         of the Registrable Securities owned by such seller; PROVIDED, that the
         Company will not be required to (i) qualify generally to do business in
         any jurisdiction where it would not otherwise be required to qualify
         but for this Section 2.4(d), (ii) subject itself to taxation in any
         such jurisdiction or (iii) consent to general service of process in any
         such jurisdiction, but the Company will be required to consent to
         service of process in actions arising out of or in connection with the
         sale of the Registrable Securities or any violation of state securities
         laws;

                  (f) use its reasonable best efforts to cause the Registrable
         Securities covered by such registration statement to be registered with
         or approved by any other governmental agencies or authorities as may be
         necessary by virtue of the business and

                                        6
<PAGE>

         operations of the Company to enable the seller or sellers thereof to
         consummate the disposition of such Registrable Securities;

                  (g) enter into customary agreements (including an underwriting
         agreement in customary form) and take such other actions as are
         required in order to expedite or facilitate the disposition of such
         Registrable Securities;

                  (h) use its reasonable best efforts to cause all such
         Registrable Securities to be listed on each securities exchange on
         which similar securities issued by the Company are then listed;

                  (i) cooperate with the Stockholders and the managing
         underwriter, if any, to facilitate the timely preparation and delivery
         of certificates representing Registrable Securities to be sold, which
         certificates shall not bear any restrictive legends after the date on
         which the applicable registration statement becomes effective; and, in
         the case of an underwritten offering, enable the Registrable Securities
         to be in the denominations and registered in such names as the managing
         underwriter may request at least two (2) days prior to any sale of the
         Registrable Securities; and

                  (j) provide a transfer agent and registrar for all Registrable
         Securities covered by such registration statement not later than the
         effective date of such registration statement.

The Company may require each seller of Registrable Securities as to which any
registration is being effected to furnish to the Company such information
regarding matters relating to such seller's Registrable Securities as are
customary and as the Company may from time to time reasonably request in writing
in order to comply with Securities Act, the rules promulgate thereunder by the
Commission and state securities laws.

         2.5      INDEMNIFICATION.

                  (a) To the extent permitted by law, I/O will indemnify and
         hold harmless each Stockholder, each of its directors and officers and
         each person who controls each Stockholder within the meaning of Section
         15 of the Securities Act, with respect to registration, qualification
         or compliance which has been effected pursuant to this Agreement,
         against all expenses, claims, losses, actions, damages or liabilities
         to the extent to which each such person is subject, including any of
         the foregoing incurred in settlement of any litigation, commenced or
         threatened, to the extent such expenses, claims, losses, damages or
         liabilities (or proceedings in respect thereof) arise out of or are
         based on any untrue statement (or alleged untrue statement) of a
         material fact contained in any registration statement, prospectus,
         offering circular or other document incident to any such registration,
         qualification or compliance, or any amendment or supplement thereto,
         incident to any such registration, qualification or compliance, or
         arise out of or are based on any omission (or alleged omission) to
         state therein a material fact required to be stated therein or
         necessary to make the statements therein, in light of the circumstances
         in which they were made, not misleading, or any violation by I/O of the
         Securities Act or any state securities laws or any rule or regulation
         promulgated under the

                                        7
<PAGE>

         Securities Act or such laws applicable to I/O in connection with any
         such registration, qualification or compliance, and I/O will reimburse
         the indemnified persons, for any legal and any other expenses
         reasonably incurred in connection with investigating, preparing or
         defending any such claim, loss, damage, liability or action, PROVIDED,
         HOWEVER, that the indemnity contained herein shall not apply to amounts
         paid in settlement of any claim, loss, damage, liability or expense if
         settlement is effected without the consent of I/O (which consent shall
         not unreasonably be withheld or delayed); PROVIDED, FURTHER, that I/O
         will not be liable to a Stockholder or its related indemnified person
         in any such case to the extent that any such claim, loss, damage,
         liability or expense arises out of or is based on any untrue statement
         or omission or alleged untrue statement or omission, made in reliance
         upon and in conformity with information furnished in writing to I/O by
         such Stockholder expressly for inclusion in such registration.
         Notwithstanding the foregoing, insofar as the foregoing indemnity
         relates to any such untrue statement (or alleged untrue statement) or
         omission (or alleged omission) made in the preliminary prospectus but
         eliminated or remedied in the amended prospectus on file with the
         Commission at the time the registration statement becomes effective or
         in the final prospectus filed with the Commission pursuant to the
         applicable rules of the Commission or in any supplement or addendum
         thereto, the indemnity agreement herein shall not inure to the benefit
         of a Stockholder if a copy of the final prospectus filed pursuant to
         such rules, together with all supplements and addenda thereto, was not
         furnished to the person or entity asserting the loss, liability, claim
         or damage at or prior to the time such furnishing is required by the
         Securities Act and I/O furnished to such Stockholder a sufficient
         number of copies of such final prospectus a reasonable period of time
         prior to the time such furnishing is required by the Securities Act.

                  (b) To the extent permitted by law, each Stockholder will, if
         securities held by such Stockholder are included in the securities as
         to which the registration, qualification or compliance is being
         effected pursuant to the terms of this Agreement, severally and not
         jointly, indemnify and hold harmless I/O, each of its directors and
         officers, each person who controls I/O within the meaning of Section 15
         of the Securities Act, and each other person selling I/O's securities
         covered by such registration statement, each of such person's officers
         and directors and each person controlling such persons within the
         meaning of Section 15 of the Securities Act, against all claims,
         losses, damages and liabilities (or actions in respect thereof) to the
         extent to which such person or entity is subject, arising out of or
         based on any untrue

                                        8
<PAGE>

         statement (or alleged untrue statement) of a material fact contained in
         any such registration statement, prospectus, offering circular or other
         document incident to any such registration, qualification or
         compliance, or arising out of or based on any omission (or alleged
         omission) to state therein a material fact required to be stated
         therein or necessary to make the statements therein, in light of the
         circumstances in which they were made, not misleading, or any violation
         by such Stockholder of the Securities Act or any state securities laws
         or any rule or regulation promulgated under the Securities Act or such
         laws applicable to such Stockholder and relating to action or inaction
         required of such Stockholder in connection with any such registration,
         qualification or compliance, and will reimburse I/O, such other
         persons, such directors, officers, persons or control persons for any
         legal or other expenses reasonably incurred in connection with
         investigating or defending any such claim, loss, damage, liability or
         action, in each case to the extent, but only to the extent, that such
         untrue statement (or alleged untrue statement) or omission (or alleged
         omission) is made in such registration statement, prospectus, offering
         circular or other document in reliance upon and in conformity with
         information furnished in writing to I/O by such Stockholder expressly
         for inclusion in such registration; PROVIDED, HOWEVER, that the
         indemnity contained herein shall not apply to amounts paid in
         settlement of any claim, loss, damage, liability or expense if
         settlement is effected without the consent of such Stockholder (which
         consent shall not be unreasonably withheld or delayed). Notwithstanding
         the foregoing, the liability of a Stockholder under this subsection (b)
         shall in no event exceed the net proceeds received by such Stockholder
         from the sale of the securities sold by the Stockholder in such
         registration giving rise to such liability.

                  (c) Each party entitled to indemnification under this Section
         2.5 (the "Indemnified Party") shall give notice to the party required
         to provide indemnification (the "Indemnifying Party") promptly after
         such Indemnified Party has actual knowledge of any action or proceeding
         commenced against, or written demand made on any such party in respect
         of which indemnity may be sought, and shall permit the Indemnifying
         Party to assume the defense of any such claim or any litigation
         resulting therefrom, provided that counsel for the Indemnifying Party,
         who shall conduct the defense of such claim or litigation, shall be
         approved by the Indemnified Party (whose approval shall not
         unreasonably be withheld or delayed), and the Indemnified Party may
         participate in such defense at such party's expense, and provided
         further that the failure of any Indemnified Party to give notice as
         provided herein shall not relieve the Indemnifying Party of its
         obligations under this Agreement unless the failure to give such notice
         is materially prejudicial to an Indemnifying Party's ability to defend
         such action and provided further, that the Indemnifying Party shall not
         assume the defense for matters as to which there is a conflict of
         interest or as to which the Indemnifying Party is asserting separate or
         different defenses, which defenses are inconsistent with the defenses
         of the Indemnified Party, in which event the costs of the Indemnified
         Parties' defense (which shall be limited to the costs of one firm, in
         addition to one firm per applicable jurisdiction to serve as local
         counsel) of such claim shall be borne by the Indemnifying Party. No
         Indemnifying Party, in the defense of any such claim or litigation,
         shall, except with the consent of each Indemnified Party, consent to
         entry of any judgment or enter into any settlement which does not
         include as an unconditional term the giving by the claimant or
         plaintiff to such Indemnified Party of a release from all liability in
         respect to such claim or litigation or which provides for other than
         money damages. No Indemnified Party shall consent to entry of any
         judgment or enter into any settlement without the consent of each
         Indemnifying Party.

                  (d) If the indemnification provided for in this Section 2.5 is
         unavailable to an Indemnified Party for any reason, then each
         Indemnifying Party, in lieu of indemnifying such Indemnified Party,
         shall contribute to the amount paid or payable by such Indemnified
         Party as a result of such losses, claims, damages or liabilities in
         such proportion as is appropriate to reflect the relative fault of I/O
         on the one hand and the applicable Stockholder or Stockholders on the
         other in connection with the statements or omissions which resulted in
         such losses, claims, damages or liabilities, as well as any other
         relevant equitable considerations; provided, however, that in no event
         will the aggregate liability of any Stockholder under this Section 2.5
         exceed the net proceeds

                                        9
<PAGE>

         received by such Stockholder from the sale of the securities sold by
         the Stockholder in the registration giving rise to such liability. The
         relative fault of I/O on the one hand and the applicable Stockholder or
         Stockholders on the other shall be determined by reference to, among
         other things, whether the untrue or alleged untrue statement of
         material fact or the omission or alleged omission to state a material
         fact relates to information supplied by I/O or by the applicable
         Stockholder or Stockholders and the parties' relevant intent,
         knowledge, access to information and opportunity to correct or prevent
         such statement or omission. I/O and the Stockholders agree that it
         would not be just and equitable if contribution pursuant to this
         Section 2.5(d) were based solely upon the number of entities from whom
         contribution was requested or by any other method of allocation which
         does not take account of the equitable considerations referred to above
         in this Section 2.5(d). The amount paid or payable by an Indemnified
         Party as a result of the losses, claims, damages and liabilities
         referred to above in this Section 2.5(d) shall be deemed to include any
         legal or other expenses reasonably incurred by such Indemnified Party
         in connection with investigating or defending any such action or claim,
         subject to the provisions of Section 2.5(c) hereof. 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 (within the
         meaning of Section 11(f)of the Securities Act). The Stockholders'
         obligations under this Section 2.5(d) shall not be joint, but shall be
         several in proportion to the net proceeds received by each Stockholder
         from the sale of the Registrable Securities by such Stockholder in the
         registration giving rise to such liability.

         2.6 WITHDRAWAL. Any Stockholder who has notified or requested the
Company to include any or all of such Stockholder's Registrable Securities in a
registration statement pursuant to Section 2.1 or Section 2.2 hereof shall have
the right to withdraw such notice or request with respect to any or all of the
Registrable Securities designated for registration thereby by giving written
notice to the Company at least fifteen (15) days prior to (i) the proposed
filing date of such registration statement, as contained in the notice given by
the Company, in the case of a registration under Section 2.1, or (ii) the actual
filing date of such registration statement, in the case of a registration under
Section 2.2. In the event of any such withdrawal, the Company shall not include
such Registrable Securities in the applicable registration, and such Registrable
Securities shall continue to be Registrable Securities in accordance with this
Agreement and shall be entitled to such registration rights granted to such
Registrable Securities pursuant to Section 2.1 or 2.2, as the case may be, as
may thereafter remain in effect.

         2.7 CERTAIN INFORMATION. Each Stockholders agrees, severally and not
jointly, with respect to any Registrable Securities included in any registration
on behalf of such Stockholder, to furnish to I/O that information regarding such
Stockholder, such Stockholder's Registrable Securities and the distribution
proposed by such Stockholder as I/O may reasonably request in writing and as
shall be required in connection with any registration, qualification or
compliance.

         2.8 RULE 144 REPORTING. With a view to making available the benefits of
certain rules and regulations of the Commission which may at any time permit the
sale of the Restricted Securities ("Restricted Securities" is defined for
purposes of this Agreement as defined in Rule

                                       10
<PAGE>

144 under the Securities Act) to the public without registration, I/O agrees,
during the term of this Agreement, to use its best lawful efforts to:

                  (a) Make and keep public information available, as those terms
         are understood and defined in Rule 144 under the Securities Act, at all
         times during which I/O is subject to the reporting requirements of the
         Securities Exchange Act of 1934, as amended (the "Exchange Act");

                  (b) File with the Commission in a timely manner all reports
         and other documents required of I/O under the Securities Act and the
         Exchange Act (at all times during which I/O is subject to such
         reporting requirements); and

                  (c) So long as any Stockholder owns any Restricted Securities,
         to furnish to the Stockholders upon request a written statement by I/O
         as to its compliance with the reporting requirements of Rule 144 and
         with regard to the Securities Exchange Act of 1934 (at all times during
         which I/O is subject to such reporting requirements), a copy of the
         most recent annual or quarterly report of I/O, and such other reports
         and documents of I/O and other information in the possession of or
         reasonably obtainable by I/O as the Stockholders may reasonably request
         in availing itself of any rule or regulation of the Commission allowing
         the Stockholders to sell securities without registration.

         2.9 UNDERWRITING. The right of each Stockholder to registration under
this Agreement under Section 2.1 shall be conditioned upon such Stockholder's
participation in the underwriting. Each of the Stockholders shall (together with
I/O and the other holders distributing their securities through the
underwriting) enter into an underwriting agreement in customary form with the
managing underwriter(s) selected for the underwriting by I/O. If the managing
underwriter(s) in a registration under Section 2.1 determines that marketing
factors require a limitation of the number of shares to be underwritten, the
Company may limit some or all of the Registrable Securities that may be included
in the registration and underwriting and, in such case, the Company shall only
include in such registration and underwriting: (i) first, all of I/O's
securities being registered for sale for I/O's own account, (ii) second,
securities held by persons and entities having registration rights pursuant to
agreements whose terms require that such securities have priority over
securities held by others, or whose terms prohibit the registration of
securities held by others, and (iii) third, securities held by persons and
entities, including the Stockholders, having registration rights pursuant to any
other agreements. The number of Registrable Securities that may be included
pursuant to clause (iii) above shall be determined by multiplying the number of
Registrable Securities sought to be registered by the Stockholders times a
fraction, the numerator of which is the number of Registrable Securities
requested to be included in the registration and underwriting by the
Stockholders, and the denominator of which is the total number of such
securities which all persons and entities described in clause (iii) above have
requested to have included in the registration and underwriting. I/O may round
the number of shares allocable to any such person to the nearest 100 shares.

                                       11
<PAGE>

3.       MISCELLANEOUS.

         3.1 GOVERNING LAW. THIS AGREEMENT SHALL BE GOVERNED IN ALL RESPECTS BY
THE INTERNAL LAWS OF THE STATE OF DELAWARE.

         3.2 NO TRANSFER; TERMINATION. These registration rights are not
transferable, except by operation of law, and shall not inure to the benefit of
any person other than the Stockholders; PROVIDED, HOWEVER, that a Stockholder
may transfer the registration rights granted hereunder or any portion thereof to
any transferee who (i) (a) holds 200,000 or more Registrable Securities after
giving effect to such transaction, or (b) is an affiliate, spouse or descendant
of such Stockholder or any entity or investment vehicle, including a
partnership, in which such Stockholder or any of its affiliates has a majority
economic interest or which is managed by such Stockholder or any of its
affiliates and (ii) agrees to be bound by the terms and conditions of this
Agreement and signs an addendum to this agreement to such effect. After such a
transfer, both the Stockholder and each such transferee shall be entitled to the
notice provided in Section 2.1 and the piggyback rights provided in Section 2,
including piggyback rights upon the registration of Registrable Securities as a
result of a Demand Registration pursuant to Section 2.2. This Agreement shall
terminate on the earlier to occur of (i) such time as the Stockholders can sell
all of their remaining Registrable Securities under Rule 144 within any three
(3) month period or (ii) such time as all of the Stockholders' Registrable
Securities may be sold pursuant to Rule 144(k) under the Securities Act.

         3.3 ENTIRE AGREEMENT; AMENDMENT. This Agreement constitutes the full
and entire understanding and agreement between the parties with regard to the
Agreement's subject matter. Any provision of this Agreement may be amended,
waived, discharged or terminated only upon the written consent of I/O and all of
the Stockholders.

         3.4 NOTICES. All notices or other communications which are required or
may be given under this Agreement shall be in writing and shall be deemed to
have been duly given when delivered in person, transmitted by telecopier and
confirmed, or mailed by registered or certified first class mail, postage
prepaid, return receipt requested to the parties hereto at the address set forth
below (as the same may be changed from time to time by notice similarly given)
or the last known business or residence address of such other person as may be
designated by either party hereto in writing.

                  If to the Stockholders:

                  If to I/O:

                  Input/Output, Inc.
                  12300 Parc Crest Drive
                  Stafford, Texas 77477
                  Attention:

         3.5 DELAYS OR OMISSIONS. Except as expressly provided herein, no delay
or omission to exercise any right, power or remedy accruing to any party to this
Agreement shall

                                       12
<PAGE>

impair any such right, power or remedy of such party nor shall it be construed
to be a waiver of any such breach or default, or an acquiescence therein, or of
or in any similar breach or default thereafter occurring; nor shall any waiver
of any single breach or default be deemed a waiver of any other breach or
default theretofore or thereafter occurring. Any waiver, permit, consent or
approval of any kind or character on the part of any party of any breach or
default under this Agreement, or any waiver on the part of any party of any
provisions or conditions of this Agreement, must be in writing and shall be
effective only to the extent specifically set forth in such writing. All
remedies either under this Agreement or by law or otherwise afforded to any
party to this Agreement, shall be cumulative and not alternative.

         3.6 COUNTERPARTS. This Agreement may be executed in any number of
counterparts, each of which shall be enforceable against the parties actually
executing such counterparts, and all of which together shall constitute one
instrument.

         3.7 SEVERABILITY. In the event that any provision of this Agreement
becomes or is declared by a court of competent jurisdiction to be illegal,
unenforceable or void, this Agreement shall continue in full force and effect
without said provision.

         3.8 TITLES AND SUBTITLES. The titles and subtitles used in this
Agreement are used for convenience only and are not considered in construing or
interpreting this Agreement.

         3.9 NO THIRD PARTY RIGHTS. Except as otherwise provided in Sections 2.5
and 3.2, this Agreement shall not create benefits on behalf of any Person who is
not a party to this Agreement, and this Agreement shall be effective only as
between the parties hereto, their successors and permitted assigns.

         3.10 NO REQUIRED SALE. Nothing in this Agreement shall be deemed to
create an independent obligation on the part of any Stockholder to sell any
Registrable Securities pursuant to any effective registration statement.

         3.1 NOMINEES FOR BENEFICIAL OWNERS. If Registrable Securities are held
by a nominee for the beneficial owner thereof, the beneficial owner thereof may,
at its option, be treated as the holder of such Registrable Securities for
purposes of any request or other action by any holder of Registrable Securities
pursuant to this Agreement (or any determination of any number or percentage of
shares constituting Registrable Securities held by any Stockholder contemplated
by this Agreement); provided, that the Company shall have received written
notice thereof from both such beneficial owner and nominee.

         3.2 SPECIFIC PERFORMANCE. The parties acknowledge that there may be no
adequate remedy at law if any party fails to perform any of its obligations
under this Agreement and that each party may be irreparably harmed by any such
failure. Accordingly, the parties agree that each party, in addition to any
other remedy to which it may be entitled at law or in equity, shall be entitled
to compel specific performance of the obligations of any other party under this
Agreement, in accordance with the terms and conditions of this Agreement, in any
court of the United States or any State thereof having jurisdiction.

         3.3 GENDER. Within this Agreement, words of any gender shall be held
and construed to cover any other gender, unless the context otherwise requires

                                       13
<PAGE>

         3.4 RECAPITALIZATION, EXCHANGES, ETC. AFFECTING THE COMMON STOCK. The
provisions of this Agreement shall apply to the full extent set forth herein
with respect to (i) the shares of Common Stock, and (ii) any and all shares of
capital stock of the Company or any successor or assignee of the Company
(whether by merger, consolidation, sale of assets or otherwise) which may be
issued in respect of, in exchange for, or in substitution for the shares of
Common Stock, by reason of any stock dividend, split, reverse split,
combination, recapitalization, reclassification, merger, consolidation or
otherwise. In the event of any change in capitalization of the Company, as a
result of any stock split, stock dividend or stock combination, the provisions
of this Agreement shall be appropriately adjusted.

                               [SIGNATURES FOLLOW]

                                       14
<PAGE>

IN WITNESS WHEREOF, the undersigned or each of their respective duly authorized
officers or representatives have executed this agreement effective upon the date
first set forth above.

                                              INPUT/OUTPUT, INC.

                                              By: /s/ J. Michael Kirksey
                                                 -------------------------------
                                              Name: J. Michael Kirksey
                                              Title: Executive Vice President
                                                     and Chief Operating Officer

THE STOCKHOLDERS

Executed by ALASTAIR JAMES HAY                  /s/ A J Hay
at Edinburgh on 23 February 2004
in the presence of the following witness:

/s/ Rona Cameron           Witness
Rona Cameron               Name
16 Charlotte Sq            Address
Edinburgh

Executed by ALAN KENNEDY FAICHNEY               /s/ Alan Faichney
at Edinburgh on 23 February 2004
in the presence of the following witness:

/s/ Rona Cameron           Witness
Rona Cameron               Name
16 Charlotte Sq            Address
Edinburgh

Executed by ROBERT GEORGE JOHNSON               /s/ A J Hay
at Edinburgh on 23 February 2004                Attorney
in the presence of the following witness:

/s/ Rona Cameron           Witness
Rona Cameron               Name
16 Charlotte Sq            Address
Edinburgh

Executed for and on behalf of                   /s/ M. Pacitti
3i PLC
at Edinburgh on 23 February 2004
by M. Pacitti
its duly authorised attorney in the
presence of the following witness:

/s/ Rona Cameron           Witness
Rona Cameron               Name
16 Charlotte Sq            Address
Edinburgh

Executed for and on behalf of                   /s/ M. Pacitti
3i GROUP PLC
at Edinburgh on 23 February 2004
by M. Pacitti
its duly authorised attorney in the
presence of the following witness:

/s/ Rona Cameron           Witness
Rona Cameron               Name
16 Charlotte Sq            Address
Edinburgh

Executed for and on behalf of                   /s/ M. Pacitti
3i PARALLEL VENTURES LP
at Edinburgh on 23 February 2004
by M. Pacitti
its duly authorised attorney in the
presence of the following witness:

/s/ Rona Cameron           Witness
Rona Cameron               Name
16 Charlotte Sq            Address
Edinburgh

Executed on behalf of                           /s/ M. Pacitti
PARALLEL VENTURES MANAGERS LIMITED
as Administrators of and attorney for
the Members of Parallel Ventures (No. 2)
Co-Investment Plan acting by its
attorney 3i Investments plc by
M. Pacitti as duly authorised
attorney for 3i Investments plc
at Edinburgh on 23 February 2004
in the presence
of the following witness:

/s/ Rona Cameron           Witness
Rona Cameron               Name
16 Charlotte Sq            Address
Edinburgh

Executed for and on behalf of                   /s/ M. Pacitti
3i UKIP II LP by
its manager 3i Investments plc
at Edinburgh on 23 February 2004
by M. Pacitti
its duly authorised attorney in the
presence of the following witness:

/s/ Rona Cameron           Witness
Rona Cameron               Name
16 Charlotte Sq            Address
Edinburgh

Executed on behalf of ANNETTA PHILLIP           /s/ A J Hay
by her duly authorised attorney
at Edinburgh on 23 February 2004
in the presence of the following witness:

/s/ Rona Cameron           Witness
Rona Cameron               Name
16 Charlotte Sq            Address
Edinburgh

Executed by IAIN MACRITCHIE                     /s/ Ian Macritchie
at Edinburgh on 23 February 2004
in the presence of the following witness:

/s/ Rona Cameron           Witness
Rona Cameron               Name
16 Charlotte Sq            Address
Edinburgh

Executed by NICK WALTERS                        /s/ Nick Walters
at Edinburgh on 23 February 2004
in the presence of the following witness:

/s/ Rona Cameron           Witness
Rona Cameron               Name
16 Charlotte Sq            Address
Edinburgh

EXECUTED by                                     /s/ N J Graham
RBS MEZZANINE LIMITED                           Duly Authorised Signatory
(for itself and as Agent and Trustee)
acting by N. Graham
in the presence of

/s/ Rona Cameron           Witness
Rona Cameron               Name
16 Charlotte Sq            Address
Edinburgh

                                       15
<PAGE>

                                     ANNEX A

                                  STOCKHOLDERS

3I GROUP PLC
3I PARALLEL VENTURES LP
3I UKIP II LP
91 Waterloo Road, London SE1 8XP, UK

ANNETTA PHILLIP
7/36 Portland Gardens, Edinburgh EH6 6NQ, UK

ALAN FAICHNEY
Swanston Old Farmhouse, Swanston, Edinburgh EH10 7DS, UK

ALASTAIR HAY
3 Spylaw Avenue, Edinburgh EH13 9LW, UK

ROBERT JOHNSON
12 Crescent Grove, London SW4 7AH, UK

RBS MEZZANINE LIMITED
42 St Andrew Square, Edinburgh, UK

IAIN MACRITCHIE
C/o MCR Holdings, Caldcoats House, Stewarton, Glasgow, UK

NICK WALTERS
C/o MCR Holdings, Caldcoats House, Stewarton, Glasgow, UK

                                       16

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