MASTER LETTER OF CREDIT AGREEMENT

Date:  April 16, 1996

To induce ABN AMRO Bank N.V. Houston Agency (the "Bank") to issue letters of
credit (as the same may be amended, the "Credits") substantially in accordance
with the Applications submitted to Bank in accordance with Paragraph 1 of this
Agreement, the undersigned, jointly and severally if there is more than one of
the undersigned (the "Applicant") agrees as follows:

1.  APPLICATIONS

  Each Application to Bank for the issuance of a Credit shall be made by
  Applicant on Bank's standard form application or other mutually acceptable
  format (the "Application"), either sent by telecopy transmission, by United
  States mail or by a Bank-supplied applicant initiation systems (i.e. Planet). 
  In the event a Bank-supplied applicant initiation system is used, Applicant
  represents and warrants that it is authorized to use such system.  In
  connection with such Applications, Bank and Applicant agree that (i) Bank is
  hereby authorized to act on any Application which Bank in good faith believes
  emanates from an authorized representative of Applicant and shall not be
  liable for any action taken in good faith with respect to Applications from
  unauthorized persons; (ii) Bank shall not be under any duty to verify the
  identity of any person submitting any Application and all such Applications
  shall be binding upon Applicant whether made with or without Applicant's
  authority, knowledge or consent; and (iii) APPLICANT WILL INDEMNIFY BANK FROM
  ALL ACTIONS, PROCEEDINGS, CLAIMS, LOSS, DAMAGE, COSTS AND EXPENSES BROUGHT
  AGAINST, INCURRED OR SUFFERED BY BANK (INCLUDING THOSE RESULTING FROM BANK'S
  OWN NEGLIGENCE) WHICH HAVE ARISEN DIRECTLY OR INDIRECTLY FROM THE ACCEPTANCE
  BY BANK OF ANY APPLICATION. IT IS THE INTENTION OF THE PARTIES THAT BANK BE
  INDEMNIFIED FOR ITS OWN NEGLIGENCE (EXCEPT GROSS NEGLIGENCE).

2.  BANK'S GENERAL OBLIGATIONS

  Bank may, in Bank's sole and absolute discretion, issue Credits hereunder
  upon the request of Applicant.  Upon Bank's issuance of a Credit, Bank's
  obligations to Applicant with respect to the Credit include good faith and
  observance of general banking usage, but shall NOT include liability or
  responsibility of any kind arising out of or in connection with:  (a)
  performance of the underlying contract for sale or other transactions between
  Applicant and the beneficiary or any other person; (b) acts, errors,
  defaults, or omissions of any person other than Bank's including any use of
  the Credit by any such person; (c) loss or destruction of any telegram,
  cable, letter, instrument, or document while in transit or in the possession
  of others; (d) knowledge or lack of knowledge of any custom or usage of any
  particular trade; (e) delivery, transmission, translation, or interpretation
  of any message, including any interruption, delay, error or omission therein;
  (f) insufficiency, lack of authorization, invalidity of, lack of genuineness,
  truthfulness, or error or fraud in any documents presented under the Credit
  or in any instructions purporting to be from Applicant or Bank's
  correspondents; (g) validity or correctness of any transfer or proper
  identity of any transferee (if the Credit is issued in transferable form);
  (h) waiver of any requirement which exists for Bank's protection and not for
  the protection of Applicant, or which waiver does not in fact materially
  prejudice Applicant; or (i) any other act or omission for which banks are
  relieved of responsibility under the "Uniform Customs & Practice for
  Documentary Credits" of the International Chamber of Commerce (hereafter, the
  "UCP") or the Uniform Commercial Code, in each case as in effect on the date
  hereof.

3.  BANK'S OBLIGATIONS CONCERNING DOCUMENTS

  (a)  Bank's obligations to Applicant relative to any Credit include Bank's
  examination of documents with reasonable care so as to ascertain that on
  their face they appear to comply with the terms of the Credit, but do NOT
  include liability or responsibility of any kind arising out of or in
  connection with: (i) validity, sufficiency, truthfulness, genuineness or
  effect of documents which appear on Bank's examination to be regular on their
  face; (ii) honor of drafts or demands for payment which appear on Bank's
  examination to be regular on their face; or (iii) the ultimate correctness of
  Bank's decision regarding documentary compliance, where Bank's decision is
  based on Bank's examination of the documents, or Bank's exercise of judgment,
  in a manner not manifestly unreasonable. Bank may in its discretion (but
  shall not be obligated to) accept documents which substantially or reasonably
  comply with the terms of the Credit.

  (b)  Unless otherwise specified in the Application, Bank may, in Bank's
  discretion, but shall not be obligated to, accept or honor (in the case of
  negotiable Credits) as complying with a Credit: (i) drafts or documents
  signed by or issued by the purported executor, agent, administrator,
  liquidation, receiver, trustee in bankruptcy, or other legal representative
  of any party designated in the Credit; (ii) drafts or documents which fail to
  bear any or adequate reference to the Credit, or notation to be made on the
  Credit, or the Credit to be surrendered, or documents to be forwarded apart
  from the draft, whether or not required by the Credit; (iii) drafts or
  documents which comply under the laws, rules, regulations, and general
  banking or trade customs and usages of the place of drawing, negotiation or
  presentation; or (iv) drafts or documents which comply with the UCP.

4.  PAYMENT; COMMISSIONS

  (a)  With respect to each Credit, Applicant shall pay Bank in United States
  currency and in immediately available  funds, by wire transfer or otherwise,
  at Bank's office identified in the Application, the amount paid or to be paid
  by Bank, Bank's agent or any other party on Bank's behalf, on each draft or
  other order, instrument or demand drawn or presented or purporting to be
  drawn or presented under a Credit (the "Item") together with all other
  amounts owing to Bank in connection therewith, such payment to be made at the
  time of honor of each Item or if so demanded by Bank, on demand in advance of
  any drawing.  In the case of Items drawn in foreign currency, such payments
  shall be at Bank's current rate of exchange for transfers to the place of
  payment in the currency in which such Item is drawn (or, if for any reason
  Bank is unable to establish such a rate of exchange, 




                                                                          2

  in an amount equal to Bank's actual cost of settlement). Applicant shall 
  reimburse the Bank in the same currency in which the Item is payable, 
  provided that at Bank's option, Applicant shall reimburse Bank in United 
  States dollars for Items payable in a foreign currency at the rate at 
  which Bank could sell such foreign currency in exchange for United States 
  dollars for transfer to the place of payment of the Item, or, if there is 
  no such rate, the United States dollar equivalent of Bank's actual cost of 
  settlement. Applicant agrees to pay Bank on demand in United States 
  dollars such amounts as Bank may be required to expend to comply with any 
  and all governmental exchange regulations now or hereafter applicable to 
  the purchase of foreign currency.

  (b)  With respect to each Credit, Applicant shall pay Bank on demand, in
  United States currency at Bank's office identified on the Application: (i) a
  non-refundable commission at such rate as Bank may establish; (ii) interest
  on all amounts due and owing to Bank, from and including the date such amount
  is paid or incurred by Bank or otherwise due and owing hereunder until such
  amount is paid in full, at a fluctuating rate equal to the lesser of (x)
  Bank's Prime Rate plus two percent (2%) per annum, and (y) the maximum
  nonusurious rate of interest permitted by applicable law from time to time in
  effect. "Prime Rate" shall mean the rate in effect from time to time as set
  by Bank and called its Prime Rate for United States dollar loans, which rate
  is not necessarily the lowest or best interest rate offered by Bank and
  interest shall be calculated on the basis of a 360-day year for actual days
  elapsed (unless such calculation would cause a usury violation, in which
  event interest shall be calculated on the basis of a year of 365 or 366 days,
  as the case may be); and (iii) all charges and expenses, including attorney's
  fees, legal expenses, court costs, and any similar costs or liabilities from
  time to time paid or incurred by Bank issuance or maintenance of the Credit,
  Bank's performance under the Credit and this Agreement, and all transactions
  (including, without limitation, the involvement of Bank in any court
  proceeding regarding the Credit) related to or contemplated by this Agreement
  (including without limitation, Bank's creation, perfection, maintenance,
  protection, exercise, enforcement or other realization of or upon Bank's
  interests, rights, and remedies) and (iv) all charges and fees payable under
  any fee schedule of Bank in effect from time to time or as otherwise agreed.

  (c)  All amounts payable by Applicant hereunder shall be paid at the office
  of Bank identified on Application, in immediately available and freely
  transferable funds at such place of payment. Bank is authorized to set off or
  charge to any account or other funds of Applicant in Bank's possession all
  obligations of Applicant owing hereunder, irrespective of the currency in
  which such account or funds are denominated.

  (d)  If, as a result of any law, regulation, treaty or directive, or any
  change therein, or in the interpretation or application thereof or Bank's
  compliance with any request or directive (whether or not having the force of
  law) from any court or governmental authority, agency or instrumentality, any
  reserve, capital requirement, premium, special deposit, special assessment or
  similar requirements against Bank's assets, deposits or credit extended by
  Bank are imposed, modified or deemed applicable and Bank shall determine
  that, by reason thereof, the cost to Bank of issuing or maintaining the
  Credit is increased, Applicant agrees to pay Bank upon demand such additional
  amount or amounts as will compensate Bank for such additional costs (but only
  to the extent such compensation does not cause the aggregate compensation to
  Bank to exceed the maximum nonusurious rate of interest permitted by
  applicable law from time to time in effect).  Determinations by Bank of the
  additional amounts required to compensate Bank in respect of the foregoing
  shall be conclusive, absent manifest error. Applicant further agrees to pay
  any applicable levies or other taxes imposed in connection with the Credit
  other than net income taxes payable by Bank, and to otherwise comply with all
  domestic and foreign laws and regulations applicable to all transactions
  under or in connection with the Credit.

  (e)  Bank may (but shall not be obligated to) make a loan to Applicant in an
  amount equal to the reimbursement obligation of Applicant under Section 4(a)
  hereof and Bank shall be hereby authorized to apply the proceeds of such loan
  to the repayment of such reimbursement obligation.  Each loan shall, except
  to the extent otherwise agreed to in writing between Applicant and Bank, be
  due on demand and shall bear interest payable on demand at the per annum rate
  set forth in Section 4(b)(ii) hereof.

5.  ASSUMPTION OF RISK BY APPLICANT; INDEMNIFICATION OF BANK BY APPLICANT;
    SUBROGATION.

  (a) Applicant's obligations to Bank hereunder are, and shall remain, absolute
  and unconditional notwithstanding any lack of enforceability of any of the
  Credits or the existence of any claim, counterclaim, defense or right of set
  off Applicant may have against Bank.

  (b)  The beneficiary or any other user of a Credit and any other drawer of
  any draft or the presenter of any demand for payment thereunder shall be
  deemed Applicant's agents, and Applicant assumes all risk, loss, liability,
  charges and expenses with respect to their acts or omissions and also with
  respect to any error, delay, misdelivery or loss in or arising out of the
  transmission of telegrams, cables, letters or other communications or
  documents or items forwarded in connection with the drafts or the Credit,
  including, without limitation, any Application. Applicant shall not be
  relieved from any obligation or liability, nor shall the terms of this
  Agreement be affected by the occurrence of any of the foregoing.  Any action
  or inaction by Bank or its correspondents in connection with a Credit or with
  instructions, drafts, documents, or merchandise relative to a Credit, shall,
  if in good faith, conclusively be deemed to have been authorized by
  Applicant, and Bank shall have no liability thereunder.

  (c)  APPLICANT SHALL INDEMNIFY BANK AND ITS CORRESPONDENTS AND SHALL DEFEND
  AND HOLD BANK AND ITS CORRESPONDENTS HARMLESS FROM AND AGAINST ANY AND ALL
  CLAIMS, DAMAGES, LOSS, COSTS, EXPENSES (INCLUDING ATTORNEYS' FEES) AND
  LIABILITIES OF ANY NATURE WHATEVER, SUSTAINED, INCURRED OR ASSERTED IN
  CONNECTION WITH ANY CREDITS (INCLUDING CONSEQUENCES OF ANY INDEMNITER'S OWN
  NEGLIGENCE), THE PAYMENT OR ACCEPTANCE OR REFUSAL TO PAY OR ACCEPT ANY DRAFT
  OR OTHER DEMAND FOR PAYMENT, AND ANY OTHER ACTION OR INACTION IN RELIANCE
  UPON THE PROVISIONS OF THIS AGREEMENT (including but not limited to any and
  all claims, damages, loss, costs, expenses and liabilities arising out of or
  resulting from the negligence (sole, ordinary, contributory or other) of the
  person to be indemnified except, only if, and to the extent that any such
  claims, damages, loss, expenses or liabilities shall have been determined 





                                                                          3

  by a court of competent jurisdiction to have been directly caused by the 
  willful misconduct or gross negligence of Bank in performing its obligations 
  under the Credit or by Bank's failure to make payment of any drawing or other
  demand for payment made in strict conformity with the Credit).  It is
  understood that in making payment under the Credit Bank's exclusive reliance
  on the documents presented to Bank in accordance with the terms of the Credit
  as to any and all matters set forth therein, whether or not any statement or
  any document presented pursuant to the Credit proves to be forged,
  fraudulent, invalid or insufficient in any respect whatsoever shall not be
  deemed willful misconduct or gross negligence of Bank.

  (d)  Bank shall be subrogated (for purposes of defending against Applicant's
  claims and proceeding against others to the extent of Bank's liability to
  Applicant) to Applicant's rights against any person who may be liable to
  Applicant on any underlying transaction; to the rights of any holder in due
  course or person with similar status against Applicant; and to the rights of
  any beneficiary or its assignee or person with similar status against
  Applicant.

  (e)  Applicant certifies that transactions in any commodities covered by this
  Agreement are not prohibited under the foreign assets control regulations of
  the United States Treasury Department and that any importation covered by
  this Agreement conforms in every respect with all existing United States
  government regulations.

6.  DEFAULT; REMEDIES.

  (a)  Applicant shall be in default under this Agreement if any of the
  following events are not cured within five days of occurrence, and Applicant
  shall immediately notify the Bank at such point: (i) any failure by Applicant
  to perform its obligations or covenants under this Agreement or any other
  agreement with Bank or instrument delivered to Bank; including without
  limitation Applicant's obligation to pay promptly all sums due to Bank; (ii)
  any failure to furnish upon demand any financial information Bank may request
  of Applicant or to permit at a reasonable time Bank's inspection of
  Applicant's books, records and accounts; (iii) any act or event evidencing or
  reasonably appearing to evidence the bankruptcy, reorganization,
  rehabilitation, arrangement, liquidation, insolvency or financial instability
  of any party signing hereto as an Applicant, or of any guarantor thereof;
  (iv) any material misrepresentation made by Applicant in connection with this
  Agreement or a Credit; (v) any default in excess of $200,000 by Applicant
  under any agreement involving the borrowing of money or the obtaining of
  credit; or (vi) any other act, event or occurrence which in Bank's sole
  judgment increases its risk. 

  (b)  Upon default, all of Applicant's obligations and liabilities to Bank, of
  whatever nature, whether contingent or absolute, shall become immediately due
  and payable WITHOUT PRESENTMENT, PROTEST, NOTICE OR DEMAND AND WITHOUT NOTICE
  OF INTENTION TO ACCELERATE OR NOTICE OF ACCELERATION, ALL OF WHICH ARE HEREBY
  WAIVED and, without limiting the foregoing and any other rights of Bank
  hereunder, Applicant shall pay to Bank within five days an amount equal to
  the available undrawn amount of all outstanding Credits. Bank shall have all
  the rights and remedies of a secured party under the Uniform Commercial Code,
  and in addition to such rights and remedies, Applicant further agrees that
  any default under this Agreement shall also be a default under all other
  agreements with Bank.

  (c)  All amounts due and payable shall accrue interest, from and including
  the date such amount is paid or incurred by Bank until payment in full, at
  the per annum rate set forth in Section 4(b)(ii) hereof.

7.  NEGATIVE PLEDGE

  Applicant shall not create, assume, incur, suffer or permit to exist any
  mortgage, pledge, encumbrance, security interest, assignment, lien or charge
  of any kind or character upon any asset of Applicant whether owned at the
  date hereof or hereafter acquired except: (i) liens for taxes, assessments or
  other governmental charges not yet due or which are being contested in good
  faith by appropriate proceedings in such a manner as not to make the property
  forfeitable; (ii) other liens, charges, and encumbrances incidental to the
  conduct of its business or the ownership of its property and assets which
  were not incurred in connection with the borrowing of money or the obtaining
  of an advance or credit, and which do not in the aggregate materially detract
  from the value of its property or assets or materially impair the use thereof
  in the operation of its business; (iii) liens arising out of judgments or
  awards against Applicant with respect to which it shall concurrently
  therewith be prosecuting an appeal or proceeding for review and with respect
  to which it shall have secured a stay of execution pending such appeal or
  proceedings for review; (iv) pledges or deposits to secure obligations under
  workmen's compensation laws or similar legislation; (v) good faith deposits
  in connection with lending contracts or leases to which Applicant is a party;
  (vi) deposits to secure public or statutory obligations of Applicant; (vii)
  liens existing on the date hereof and disclosed in writing to Bank; (viii)
  assignments under Applicant's ongoing note purchase programs not to exceed
  $50,000,000 in aggregate; (ix) mortgages against Applicant's property in
  Stafford, Texas incurred with the expansion of Applicant's manufacturing
  facilities not to exceed $15,000,000 in aggregate; and (x) liens and
  encumbrances assumed under purchase money security agreements for equipment
  purchases not to exceed $25,000,000 in aggregate.

8.  WAIVER BY BANK; ACTS NOT AFFECTING AGREEMENT.

  Bank shall have no duty to exercise any of its rights hereunder, and shall
  not be liable for any failure to do so or delay in doing so.  No such failure
  or delay on the part of Bank or its correspondents shall operate as a waiver,
  and no notice to or demand by the Bank or its correspondents shall be deemed
  a waiver of Bank's right to take any other or further action without notice
  or demand. Bank's rights-including all security interests in Collateral, and
  Applicant's obligations and liabilities under this Agreement shall continue
  unimpaired and this Agreement shall remain binding upon each party hereto
  signing as an Applicant, notwithstanding: (a) release or substitution of any
  Collateral or any right or interest therein (b) extension of the maturity or
  time for presentation of drafts, acceptances, or documents; (c) any other
  modification of the terms of any Credit at the request of any party hereto
  signing as an Applicant, with or without notification to any other party; or
  (d) any increase in the amount 



                                                                          4

  of any Credit at the request of any party hereto.  No delay, extension of 
  time, renewal, compromise or other indulgence which Bank may permit in 
  connection with any of Bank's rights hereunder shall impair those rights, 
  and Bank shall not be deemed to have waived any rights unless such waiver 
  is in writing and signed by Bank or its authorized agent; nor shall any 
  such waiver constitute a waiver of any other right or of the same right at 
  any future time. Bank 's acceptance or honor of drafts or issuance of a 
  Credit varying from the terms of this Agreement will not affect the terms 
  and conditions applicable to any other drafts or Credits, whether such 
  other drafts or Credits are then existing or subsequently arising.
  
9.  SOLE OBLIGATION OF BANK. 

  Without limiting any other provision herein, Bank is hereby expressly
  authorized and directed to honor any request for payment which is made under
  and in compliance with the terms of any Credit without regard to, and without
  any duty on the part of Bank to inquire into, the existence of any disputes
  or controversies between Applicant, the beneficiary of a Credit or any other
  person, firm or corporation, or the respective rights, duties or liabilities
  of any of them or whether any facts or occurrences represented in any of the
  documents presented under a Credit are true or correct.  Furthermore,
  Applicant fully understands and agrees that Bank's sole obligation to
  Applicant shall be limited to honoring requests for payment made under and in
  compliance with the terms of any Credit and this Agreement and Bank's
  obligation remains so limited even if Bank may have assisted Applicant in the
  preparation of the wording of any Credit or any documents required to be
  presented thereunder or that Bank may otherwise be aware of the underlying
  transaction giving rise to any Credit and this Agreement.

10. DURATION OF AGREEMENT, AGREEMENT BINDING UPON SUCCESSORS, INDEMNITY.

  This Agreement shall remain in full force and effect until Bank has actually
  received written notice to the contrary from the Applicant, and after receipt
  of such notice shall continue in full force and effect as to all transactions
  between Bank and Applicant commenced prior to the date of such receipt. All
  indemnities, covenants, agreements, representations and warranties made in
  this Agreement shall survive the issuance by Bank of the Credits and shall
  continue in full force and effect so long as any Credit, or any portion
  thereof, shall be unexpired or any sums drawn thereunder or other amounts
  owing hereunder shall remain unpaid, provided, however, that the provisions
  of Section 4(b)(iii), 4(d), 6(c), 11, 13, 14(b), 14(c) and 14(k) shall
  survive the termination of this Agreement. This Agreement shall not be
  revoked or impaired by the death of any party hereto, by the revocation or
  release of any obligations hereunder of any one or more parties hereto (or if
  any party hereto shall be a partnership, by any changes in the parties
  composing the partnership).  If this Agreement is terminated or revoked as to
  any party for any reason, Applicant shall indemnify and hold Bank harmless
  from any loss incurred in acting hereunder prior to the actual receipt of
  written notice of such termination or revocation.  The invalidity or lack of
  enforceability of any provision hereof shall not affect the validity or
  enforceability of any other provision hereof.  If this Agreement is signed by
  two or more Applicants, it shall constitute the joint and several agreement
  of such parties, provided that the Designated Party, as set forth below,
  shall have the exclusive right to issue all instructions relating to the
  Credits including, without limitation, instructions as to the disposition of
  documents and any unutilized funds, waiver of discrepancies and to agree with
  Bank upon any amendments, modifications, extensions, renewals or increases in
  the Credits or further financing or refinancing of any transaction effected
  hereunder, irrespective of whether the same may now or hereafter affect the
  rights of any party hereto or of their legal representatives, heirs or
  assigns.  The Designated Party shall have specimen signatures on file with
  Bank and Bank may give notices to the Designated Party without notice to any
  other party.  The term "Applicant" as used herein shall mean and include each
  party signing this Agreement as applicant.


12. LAW GOVERNING 

  The Credit and this Agreement shall be governed by and construed in
  accordance with the laws of the State of Texas applicable to contracts made
  and to be wholly performed within such State.  Unless inconsistent with such
  state law or except so far as otherwise expressly stated in the Credit, the
  Credit and this Agreement are subject to the terms of the UCP in effect on
  the date of the Application; provided, however, without limiting the
  foregoing, Articles 41 and 43 of the UCP 500 (or their counterparts under any
  successor UCP) shall have no application to the Credits or this Agreement. 
  In the absence of proof expressly to the contrary, the UCP shall serve as
  evidence of general banking usage.

13. GROSS-UP PROVISION 

  Any and all payments made to Bank hereunder shall be made free and clear of,
  and without deduction or withholding for, any present or future taxes,
  levies, imposts, deductions, charges or withholdings of any nature, and all
  liabilities with respect thereto, excluding taxes imposed on net income of
  Bank and all income and franchise taxes of the United States and any
  political subdivision thereof imposed on Bank (all such non-excluded taxes,
  levies, imposts, deductions, charges, withholdings and liabilities are
  referred to herein as "Taxes").  If Applicant shall be required by law to
  deduct any Taxes from or in respect to any sum payable hereunder (i) the sum
  payable shall be increased as may be necessary so that after making all
  required deductions (including deductions applicable to additional sums
  payable under this Section 12(i), Bank shall receive an amount equal to the
  sum Bank would have received had no deductions been made; (ii) Applicant
  shall make all such deductions; and (iii) Applicant shall pay the full amount
  deducted to the relevant taxation authority or other authority in compliance
  with applicable law. APPLICANT SHALL INDEMNIFY BANK for the full amount of
  Taxes (including, without limitation, any Taxes imposed by any jurisdiction
  on amounts payable hereunder) paid by Bank and any liability (including
  penalties, interest and expenses) arising therefrom or with respect thereto,
  whether or not such Taxes were correctly or legally asserted.  Payment upon
  this indemnification shall be made within thirty (30) days from the date Bank
  makes written demand therefore. 



                                                                          5


  Within thirty (30) days after date of the payment of Taxes, Applicant will 
  furnish to Bank the original or certified copy of a receipt evidencing 
  payment thereof.

14. OTHER PROVISIONS.

  (a)  If any of the Credits shall contain any provision for automatic renewal,
  Applicant acknowledges and agrees that Bank is under no obligation to allow
  such renewal to occur and any such renewal shall remain within the sole and
  absolute discretion of Bank.  Applicant hereby irrevocably consents to the
  automatic renewal of each such Credit in accordance with its terms should
  Bank decide to allow such renewal to occur; provided, however, that Applicant
  shall have the right to request Bank to disallow such renewal on the
  condition that Applicant shall give Bank prior written notice of such request
  not less than thirty (30) days prior to the deadline imposed upon Bank for
  notification to the beneficiary of non-renewal of the Credit.

  (b)  APPLICANT SHALL INDEMNIFY BANK against any loss incurred by Bank as a
  result of any judgment or order being given or made for the payment of any
  amount due hereunder in a particular currency (the "Currency of Account") and
  such judgment or order being expressed in a currency (the "Judgment
  Currency") other than the Currency of Account and as a result of any
  variation having occurred in the rates of exchange between the date which
  such amount is converted into the Judgment Currency and the date of actual
  payment pursuant thereto.  The foregoing indemnity shall constitute a
  separate and independent obligation of Applicant.

  (c)  Each party signing as Applicant and any guarantor thereof agrees that if
  any amount paid to Bank hereunder is rescinded or must be otherwise restored
  or returned by Bank due to the insolvency, bankruptcy, liquidation or
  reorganization of any party hereto, each party's obligations hereunder with
  respect to each such amount shall be reinstated to the same extent as if such
  payment had not been made.

  (d)  Applicant authorizes Bank to set forth the terms of each Application in
  the Credit corresponding to such Application in such language as Bank deems
  appropriate, with such variations from such terms as Bank may in its
  discretion determine to be necessary (which determination shall be
  conclusive) and not materially inconsistent with such Application.  If
  Applicant, or in the case of more than one Applicant, the Designated Party, 
  does not notify Bank of any inconsistencies in such Credit within ten (10)
  calendar days of its issuance, Applicant agrees that such Credit is
  conclusively presumed to be in proper form.  Upon its receipt of timely
  notice of any discrepancy in any Credit, Bank will endeavor to obtain the
  consent of the confirming bank (if any) and the beneficiary for an
  appropriate modification to the Credit; provided, however that Bank shall
  assume no liability or responsibility for its failure to obtain such consent.
  

  (e)  No party to this Agreement may assign its rights or obligations under
  this Agreement without the prior written consent of Bank, except that the
  obligations of Bank under this Agreement may be provided or fulfilled by any
  affiliate of Bank so long as Bank assumes full responsibility for such
  obligations.

  (f)  This Agreement and any exhibits hereto constitute the entire agreement
  and contract between the parties and supersede any and all prior agreements,
  proposals, negotiations and representations pertaining to the obligations and
  duties to be performed under this Agreement.  No amendments or modifications
  of this Agreement shall be valid unless evidenced in writing and signed by or
  on behalf of Applicant and Bank. 

  (g)  Except as otherwise provided in this Agreement, all notices required to
  be given pursuant to this Agreement shall be effective when received, and
  shall be sufficient if given in writing, hand delivered, sent by First Class
  United States Mail, postage prepaid, by telecopier or air courier and
  addressed to the appropriate party at its address as shown on the signature
  page hereof or at such other address as the sending party shall have been
  advised in writing.  

  (h)  Any provision of this Agreement which is prohibited or unenforceable in
  any jurisdiction shall, as to such jurisdiction, be ineffective to the extent
  of such prohibition or lack of enforceability without invalidating the
  remaining provisions hereof or affecting the validity or enforceability of
  such provision in any other jurisdiction; wherever possible, each provision
  of this Agreement shall be interpreted in such manner as to be effective and
  valid under applicable law. 

  (i)  This Agreement may be executed in any number of counterparts and by
  different parties hereto in separate counterparts, each of which when so
  executed and delivered shall be deemed to be an original and all of which
  taken together shall constitute but one and the same instrument.  

  (j)  Regardless of the expiration date of any Credit, Applicant shall remain
  liable hereunder until Bank is released from liability by every person, firm,
  corporation or other entity which is entitled to draw or demand payment under
  the Credit.

  (k)  Applicant agrees to indemnify and hold Bank harmless from each and every
  claim, demand, liability, loss, cost or expense, including, but not limited
  to, attorney's fees and court costs any and all claims, damages, loss, costs,
  expenses and liabilities arising out of or resulting from the negligence
  (sole, ordinary, contributory or other) of the person to be indemnified which
  may arise or be created by Bank's acceptance of telecommunication
  instructions in connection with the Credit, including, but not limited to,
  telephone or facsimile instructions in connection with any waiver of
  discrepancies.

  (l)  Applicant, or in the case of more than one person signing as Applicant,
  the Designated Party, agrees to examine promptly all instruments and
  documents delivered to Applicant or the Designated Party, as the case may be,
  from time to time and in the event Applicant or the Designated Party shall
  have any claim of non-compliance with their instructions or of discrepancies
  or other irregularity, Applicant or the Designated Party, as the case may be,
  shall immediately notify Bank thereof in writing. Applicant and the
  Designated Party shall 



                                                                          6

  conclusively be deemed to have waived any such claim against Bank unless 
  such immediate notice is given as stated above.

  (m)  For multiple parties signing as Applicant, such parties may request that
  the Credit be issued with the name of one of Applicants, and agree that such
  Applicant shall be the Designated Party for the purposes of this Agreement.

  (n)  The parties hereto each hereby submits to the jurisdiction of the courts
  of the State of Texas, the venue of which shall be in the County of Harris
  and the United States District Court for the Southern District of Texas, as
  well as to the jurisdiction of all courts to which an appeal may be taken or
  other review sought from the aforesaid courts, for the purpose of any suit,
  action or other proceeding arising out of Applicant's obligations under or
  with respect to this Agreement and the Credits and expressly waives any and
  all objections it may have as to venue in any such courts. BANK AND APPLICANT
  EACH WAIVES TRIAL BY JURY IN ANY ACTION, PROCEEDING OR COUNTERCLAIM BROUGHT
  BY EITHER OF THEM AGAINST THE OTHER ON ANY MATTER WHATSOEVER (INCLUDING,
  WITHOUT LIMITATION, ANY ACTION, PROCEEDING OR COUNTERCLAIM ARISING OUT OF OR
  IN ANY WAY CONNECTED WITH THIS AGREEMENT, THE CREDITS, ANY OTHER DOCUMENTS
  EXECUTED IN CONNECTION HEREWITH OR ANY OF THE TRANSACTIONS CONTEMPLATED
  HEREIN OR THEREIN).  No party to this Agreement, including but not limited to
  any assignee or successor of a party, shall seek a jury trial in any lawsuit,
  proceeding, counterclaim, or any other litigation procedure based upon, or
  arising out of this Agreement, the Credits, any related instruments, any
  Collateral or the dealings or the relationship between the parties.  No party
  will seek to consolidate any such action in which a jury trial has been
  waived, with any other action in which a jury trial cannot be or has not been
  waived.  THE PROVISIONS OF THIS PARAGRAPH HAVE BEEN FULLY DISCUSSED BY THE
  PARTIES HERETO WITH LEGAL COUNSEL, AND THESE PROVISIONS SHALL BE SUBJECT TO
  NO EXCEPTIONS.  NO PARTY HAS IN ANY WAY AGREED WITH OR REPRESENTED TO ANY
  OTHER PARTY THAT THE PROVISIONS OF THIS PARAGRAPH WILL NOT BE FULLY ENFORCED
  IN ALL INSTANCES.

IN WITNESS WHEREOF, Applicant and Bank have caused this Agreement to be duly
executed by their respective authorized officers as of the day and year first
above written.

           APPLICANT                                  BANK
        INPUT/OUTPUT, INC.             ABN AMRO Bank N.V. Houston Agency
                                   By: ABN AMRO North America, Inc., as agent


By: /s/  Robert P. Brindley                By: /s/ Rebecca S. McCulloch
    ---------------------------------          -------------------------------
         Robert P. Brindley                        Rebecca S. McCulloch
  Senior Vice President and Chief              Vice President and Director
         Financial Officer



                                           By: /s/ Jonathan C. Homeyer
                                               -------------------------------
                                                   Jonathan C. Homeyer
                                                         Officer

Address:                                   Address:
Input/Output, Inc.                         ABN AMRO Bank
12300 Parc Crest Drive                     Three Riverway, Suite 1700
Stafford, Texas 77477                      Houston, Texas 77056