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                                                                   EXHIBIT 10.23

                                LEASE AGREEMENT

         THIS LEASE AGREEMENT, made and entered into by and between Whitson
Properties, L.C., a Texas limited liability company, hereinafter referred to as
"Landlord", and Span Instruments, Inc., a Texas corporation, hereinafter
referred to as "Tenant";

                              W I T N E S S E T H:

         1. Premises and Term. In consideration of the obligation of Tenant to
pay rent herein provided, and in consideration of the other terms, provisions
and covenants hereof, Landlord hereby demises and leases to Tenant, and Tenant
hereby takes from Landlord, certain premises described on Exhibit "A" attached
hereto and incorporated herein by reference, together with all rights,
privileges, easements, appurtenances, and immunities belonging to or in any way
pertaining to the premises and together with the buildings and other
improvements situated or to be situated upon said premises (said real property,
buildings and improvements being hereinafter referred to as the "premises").

         TO HAVE AND TO HOLD the premises for a term commencing on the
"Commencement Date", as hereinafter defined, and ending two hundred (200) months
thereafter, provided, however, that, in the event the "Commencement Date" is a
date other than the first day of a calendar month, said term shall extend for
said number of months in addition to the remainder of the calendar month
following the "Commencement Date".

         The "Commencement Date" shall be March 1, 1996. Tenant acknowledges
that it has inspected and accepts the premises, and specifically the buildings
and improvements comprising the same, in their present condition as suitable for
the purpose for which the premises are leased. The taking of possession by
Tenant shall be deemed conclusively to establish that said buildings and other
improvements are in good and satisfactory condition as of when possession was
taken. Tenant further acknowledges that no representations as to the repair of
the premises, nor promises to alter, remodel or improve the premises have been
made by Landlord, unless such are expressly set forth in this lease.

         2. Rent. Tenant agrees to pay to Landlord rent for the premises in
advance, without demand, deduction or set off, in monthly installments of
$20,300.00. One such monthly installment shall be due and payable on the date
hereof and a like monthly installment shall be due and payable, without demand,
on or before the first day of each calendar month succeeding the "Commencement
Date" during the hereby demised term, except that the rental payment for any
fractional calendar month at the commencement of the lease term shall be
prorated.

         3. Use. During the term of this lease, the premises shall be used for
any lawful purpose. Tenant shall, at its own cost and expense, obtain any and
all licenses and permits necessary for any such use. Tenant shall comply with
all governmental laws, ordinances and regulations applicable to the use of the
premises, including, but not limited to, the Americans With Disabilities Act,
and shall promptly comply with all governmental orders and directives for the
correction, prevention and abatement of nuisances in or upon or connected with
the premises, all at Tenant's sole expense. Tenant shall not permit any
objectionable or unpleasant
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odors, smoke, dust, gas, noise or vibrations to emanate from the premises.
Without Landlord's prior written consent, Tenant shall not receive, store or
otherwise handle any product, material or merchandise which is explosive or
highly inflammable. Tenant will not permit the premises to be used for any
purpose or in any manner which would render the insurance thereon void or the
insurance risk more hazardous or cause the State Board of Insurance or other
insurance authority to disallow any sprinkler credits.

         4. Taxes.

         A. Tenant agrees to pay, before they become delinquent, all taxes and
assessments and other governmental charges of any kind and nature whatsoever
(hereinafter collectively referred to as the "taxes") lawfully levied or
assessed against the premises. Tenant shall furnish to Landlord, not later than
twenty (20) days before the date any such taxes become delinquent, official
receipts of the appropriate taxing authority or other evidence satisfactory to
Landlord evidencing payment thereof. If Tenant should fail to pay any taxes
required to be paid by Tenant hereunder, in addition to any other remedies
provided herein, Landlord may, if it so elects, pay such taxes.

         B. If, at any time during the term of this lease, the present method of
taxation shall be changed so that in lieu of the whole or any part of any taxes
levied, assessed or imposed on real estate and the improvements thereon, there
shall be levied, assessed or imposed on Landlord a capital levy or other tax
directly on the rents received therefrom and/or a franchise tax, assessment,
levy or charge measured by or based, in whole or in part, upon such rents for
the present or any future building or buildings on the premises, then all such
taxes, assessments, levies or charges, or the part thereof so measured or based,
shall be deemed to be included within the term "taxes" for the purposes hereof.

         C. Tenant may, at its sole cost and expense, in its own name and/or in
the name of Landlord, dispute and contest any taxes by appropriate proceedings
diligently conducted in good faith, but only after Tenant has deposited with
Landlord the amount so contested and unpaid, which shall be held by Landlord
without obligation for interest until the termination of the proceedings, at
which time the amount deposited shall be applied by Landlord toward the payment
of the items held valid (plus any court costs, interest, penalties, and other
liabilities associated with the proceedings), and Tenant's share of any excess
shall be returned to Tenant. Tenant further agrees to pay to Landlord, upon
demand, Tenant's share (as among all tenants who participated in the contest) of
all court costs, interest, penalties, and other liabilities relating to such
proceedings. Tenant hereby indemnifies and agrees to hold harmless the Landlord
from and against any cost, damage, or expense (including attorneys' fees) in
connection with any such proceedings.

         D. Any payment to be made pursuant to this Paragraph 4, with respect to
the real estate tax year in which this lease commences or terminates, shall be
prorated.

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         5. Repairs and Maintenance. Tenant shall, at its own cost and expense,
keep and maintain all parts of the premises in good condition, promptly making
all necessary repairs and replacements, interior and exterior, structural and
non-structural, ordinary and extraordinary, including, but not limited to,
windows, glass and plate glass, doors and any special office entry, walls and
finish work, floors and floor covering, roof, foundations, down spouts, gutters,
heating and air conditioning systems, dock boards, truck doors, dock bumpers,
paving, plumbing work and fixtures, termite and pest extermination, regular
removal of trash and debris, regular mowing of any grass, trimming, weed removal
and general landscape maintenance, including keeping the parking areas,
driveways, alleys and the whole of the premises in a clean and sanitary
condition. Tenant shall at its own cost and expense repaint exterior overhead
doors, canopies, entries, handrails, gutters, and other exposed parts of the
building which reasonably require periodic repainting to prevent deterioration
or to maintain aesthetic standards.

         6. Alterations. Tenant shall not make any material alterations,
additions or improvements to the premises without the prior written consent of
Landlord. Tenant may, without the consent of Landlord, but at its own cost and
expense and in a good workmanlike manner make such minor alterations, additions
or improvements or erect, remove or alter such partitions, or erect such
shelves, bins, machinery and trade fixtures as it may deem advisable, without
altering the basic character of the building or improvements and without
overloading or damaging such building or improvements, and in each case
complying with all applicable governmental laws, ordinances, regulations and
other requirements. All alterations, additions, improvements and partitions
erected by Tenant shall be and remain the property of Tenant during the term of
this lease, and Tenant shall, unless Landlord otherwise elects as hereinafter
provided, remove all alterations, additions, improvements and partitions erected
by Tenant and restore the premises to their original condition by the date of
termination of this lease; provided, however, that if Landlord so elects prior
to termination of this lease, such alterations, additions, improvements and
partitions shall become the property of Landlord as of the date of termination
of this lease and shall be delivered up to the Landlord with the premises. All
shelves, bins, machinery and trade fixtures shall be and remain property of
Tenant and may be removed by Tenant prior to the termination of this lease if
Tenant so elects, and shall be removed if required by Landlord; upon any such
removal Tenant shall restore the premises to their original condition. All such
removals and restoration shall be accomplished in a good workmanlike manner so
as not to damage the primary structure or structural qualities of the buildings
and other improvements situated on the premises. If Landlord requires the that
shelves, bins, machinery and trade fixtures be removed and they are not removed
prior to termination of this Lease, Landlord may store said shelves, bins,
machinery and trade fixtures at the premises or at some other location for a
period of up to 60 days after termination of this Lease. If the shelves, bins,
machinery and trade fixtures have not been claimed within said 60 day period
they shall conclusively be deemed to have been abandoned by Tenant and may be
appropriated, sold, destroyed or otherwise disposed of by Landlord without
notice to Tenant or to any other person and without obligation to account for
them. Tenant will pay Landlord all expenses incurred in connection with
Landlord's disposition of such property, including without limitation the cost
of repairing any damage to the building or the premises caused by removal of
such property. Tenant's obligation to observe and perform this covenant will
survive the end of this Lease.

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         7. Signs. Tenant shall have the right to install signs upon the
premises only when first approved in writing by Landlord and subject to any
applicable governmental laws, ordinances, regulations and other requirements.
Tenant shall remove all such signs by the termination of this lease. Such
installations and removals shall be made in such manner as to avoid injury to or
defacement of the building and other improvements, and Tenant shall repair any
injury or defacement, including, without limitation, discoloration caused by
such installation or removal.

         8. Inspection. Landlord and Landlord's agents and representatives shall
have the right to enter and inspect the premises at any reasonable time during
business hours for the purpose of ascertaining the condition of the premises or
in order to make such repairs as may be required or permitted to be made by
Landlord under the terms of this lease. During the period that is six (6) months
prior to the end of the term hereof, Landlord and Landlord's agents and
representatives shall have the right to enter the premises at any reasonable
time during business hours for the purpose of showing the premises, and shall
have the right to erect on the premises a suitable sign indicating that the
premises are available. Tenant shall give written notice to Landlord at least
thirty (30) days prior to vacating the premises and shall arrange to meet with
Landlord for a joint inspection of the premises at the time of vacating. In the
event of Tenant's failure to give such notice or arrange such joint inspection,
Landlord's inspection at or after Tenant's vacating the premises shall be
conclusively deemed correct for purposes of determining Tenant's responsibility
for repairs and restoration.

         9. Utilities. Tenant shall pay for all water, gas, heat, light, power,
telephone, sewer, sprinkler charges and other utilities and services used on or
from the premises, together with any taxes, penalties, surcharges or the like
pertaining thereto, and maintenance charges for utilities, and shall furnish all
electric light bulbs and tubes. If any such services are not separately metered
to Tenant, Tenant shall pay a reasonable proportion, as determined by Landlord,
of all charges jointly metered with other premises. Landlord shall in no event
be liable for any interruption or failure of utility services on the premises.

         10. Assignment and Subletting. Tenant shall not have the right to
assign this lease or to sublet the whole or any part of the premises without the
prior written consent of Landlord. Notwithstanding any permitted assignment or
subletting, Tenant shall at all times remain directly, primarily and fully
responsible and liable for the payment of the rent herein specified and for
compliance with all of Tenant's other obligations under the terms, provisions
and covenants of this lease. Upon the occurrence of an "event of default" as
hereinafter defined, if the premises or any part thereof are then assigned or
sublet, Landlord, in addition to any other remedies herein provided or provided
by law, may at its option collect directly from such assignee or subtenant all
rents becoming due to Tenant under such assignment or sublease and apply such
rent against any sums due to Landlord from Tenant hereunder, and no such
collection shall be construed to constitute a novation or a release of Tenant
from the further performance of Tenant's obligations hereunder.

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         11. Insurance, Fire and Casualty Damage.

         A. Tenant, at Tenant's expense, agrees to maintain insurance covering
the building of which the premises are a part in an amount not less than eighty
percent (80%) (or such greater percentage as may be necessary to comply with the
provisions of any co-insurance clauses of the policy) of the "replacement cost"
thereof as such term is defined in the Replacement Cost Endorsement to be
attached thereto, insuring against the perils of Fire, Lightning, Extended
Coverage, Vandalism and Malicious Mischief, extended by Special Extended
Coverage Endorsement to insure against all other Risks of Direct Physical Loss.
All such coverages and endorsements shall be as defined, provided and limited in
the standard bureau forms prescribed by the insurance regulatory authority for
the State of Texas for use by insurance companies admitted in such state for the
writing of such insurance on risks located within such state. Landlord shall be
named as an additional insured on all policies. Any mortgagee of the premises
shall be listed as such on all policies as well. Certified copies of such
policies, together with receipt evidencing payment of premiums therefor, shall
be delivered to Landlord prior to the Commencement Date of this lease. Not less
than fifteen (15) days prior to the expiration date of any such policies,
certified copies of the renewals thereof (bearing notations evidencing the
payment of renewal premiums) shall be delivered to Landlord. Such policies shall
further provide that not less than thirty (30) days' written notice shall be
given to Landlord before such policy may be cancelled or changed to reduce the
insurance provided thereby.

         B. If the buildings situated upon the premises should be damaged or
destroyed in whole or in part for any reason whatsoever, regardless of whether
or not the same is caused by any peril covered by the insurance to be provided
by Tenant under subparagraph 11A above, Tenant shall give immediate notice
thereof to Landlord, and Tenant shall at its sole cost and expense thereupon
proceed with reasonable diligence to rebuild and repair such buildings to
substantially the condition in which they existed prior to such damage or
destruction, subject to Landlord's prior written approval of the plans and
specifications for such rebuilding and repairing. Landlord shall allow Tenant a
fair diminution of rent during the time and to the extent the premises are unfit
for occupancy as a result of any such damage or destruction. Subject to
Paragraph 11C below, Tenant shall be entitled to use all insurance proceeds
payable under the policies described in Paragraph 11A above.

         C. Notwithstanding anything herein to the contrary, in the event the
holder of any indebtedness secured by a mortgage or deed of trust covering the
premises requires that the insurance proceeds be applied to such indebtedness,
then Landlord shall have the right to terminate this lease by delivering written
notice of termination to Tenant within fifteen (15) days after such requirement
is made by any such holder, whereupon Tenant shall assign to Landlord all rights
to any insurance proceeds payable under the insurance required under
subparagraph 11A above, and all rights and obligations hereunder shall cease and
terminate.

         D. Each of Landlord and Tenant hereby releases the other from any and
all liability or responsibility to the other or any person claiming through or
under them by way of subrogation or otherwise for any loss or damage to property
caused by fire or any other perils

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insured in policies of insurance covering such property, even if such loss or
damage shall have been caused by the fault or negligence of the other party, or
anyone for whom such party may be responsible; provided, however, that this
release shall be applicable and in force and effect only with respect to loss or
damage occurring during such times as the releasor's policies shall contain a
clause or endorsement to the effect that any such release shall not adversely
affect or impair said policies or prejudice the right of the releasor to recover
thereunder and then only to the extent of the insurance proceeds payable under
such policies. Each of Landlord and Tenant agrees that it will request its
insurance carriers to include in its policies such a clause or endorsement.

         12. Liability. Landlord shall not be liable to Tenant or Tenant's
employees, agents, patrons or visitors, or to any other person whomsoever, for
any injury to person or damage to property on or about the premises, resulting
from and/or caused in part or whole by the negligence or misconduct of Tenant,
its agents, servants or employees, or of any other person entering upon the
premises, or caused by the buildings and improvements located on the premises
becoming out of repair, or caused by leakage of gas, oil, water or steam, or by
electricity emanating from the premises, or due to any cause whatsoever, and
Tenant hereby covenants and agrees that it will at all times indemnify and hold
safe and harmless the property, Landlord (including without limitation the
trustee and beneficiaries if Landlord is a trust), and Landlord's agents and
employees from any loss, liability, claims, suits, costs, expenses, including,
without limitation, attorneys' fees and damages, both real and alleged, arising
out of any such damage or injury. Tenant shall procure and maintain throughout
the term of this lease, at its sole cost and expense, comprehensive general
liability insurance with broad form extensions covering claims for personal and
bodily injury or property damage occurring in, on, under, within, upon or about
the premises, or as a result of operations thereon (including contractual
liability covering indemnities set forth in this lease), for limits, unless
otherwise agreed by Landlord, of not less than $1,000,000.00 combined single
limit for personal and bodily injury or property damage. All such policies shall
be procured by Tenant from responsible insurance companies licensed to do
business in Texas which are satisfactory to Landlord. Certified copies of such
policies, together with receipt evidencing payment of premiums therefor, shall
be delivered to Landlord prior to the Commencement Date of this lease. Not less
than fifteen (15) days prior to the expiration date of any such policies,
certified copies of the renewals thereof (bearing notations evidencing the
payment of renewal premiums) shall be delivered to Landlord. Such policies shall
further provide that not less than thirty (30) days' written notice shall be
given to Landlord before such policy may be cancelled or changed to reduce the
insurance provided thereby.

         13. Condemnation.

         A. If the whole or any substantial part of the premises should be taken
for any public or quasi-public use under governmental law, ordinance or
regulation, or by right of eminent domain, or by private purchase in lieu
thereof, and the taking would prevent or materially interfere with the use of
the premises for the purpose for which they are then being used, this lease
shall terminate and the rent shall be abated during the unexpired portion of
this lease, effective when the physical taking of said premises shall occur.

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         B. If part of the premises shall be taken for any public or
quasi-public use under any governmental law, ordinance, or regulation, or by
right of eminent domain, or by private purchase in lieu thereof, and this lease
is not terminated as provided in subparagraph 13A above, this lease shall not
terminate, but the rent payable hereunder during the unexpired portion of this
lease shall be reduced to such extent as may be fair and reasonable under all of
the circumstances.

         C. In the event of any such taking or private purchase in lieu thereof,
all compensation awarded for any taking (or sale proceeds in lieu thereof) shall
be the sole property of the Landlord, and Tenant shall have no claim thereto.

         14. Holding Over. Tenant will, at the termination of this lease by
lapse of time or otherwise, yield up immediate possession to Landlord. In the
event of any holding over by Tenant or any of its successors in interest after
the termination of this lease, unless the parties hereto otherwise agree in
writing, the hold-over tenancy shall be subject to termination by Landlord at
any time upon not less than five (5) days' advance written notice, or by Tenant
at any time upon not less than thirty (30) days' advance written notice, and all
of the other terms and provisions of this lease shall be applicable during that
period. No holding over by Tenant, whether with or without consent of Landlord,
shall operate to extend this lease except as otherwise expressly provided.

         15. Quiet Enjoyment. Landlord represents and warrants that it has full
right and authority to enter into this lease and that Tenant, upon paying the
rental herein set forth and performing its other covenants and agreements herein
set forth, shall peaceably and quietly have, hold, and enjoy the premises for
the term hereof without hindrance or molestation from Landlord, subject to the
terms and provisions of this lease.

         16. Events of Default. The following events shall be deemed to be
events of default by Tenant under this lease:

                  (a) Tenant shall fail to pay any installment of the rent
         hereby reserved when due, or any payment with respect to taxes
         hereunder when due, or any other payment or reimbursement to Landlord
         required herein when due, and such failure shall continue for a period
         of ten (10) days after written notice thereof to Tenant.

                  (b) Tenant shall become insolvent, or shall make a transfer in
         fraud of creditors, or shall make an assignment for the benefit of
         creditors.

                  (c) Tenant shall file a petition for relief under any section
         or chapter of the United States Bankruptcy Code, as amended, or under
         any similar law or statute of the United States or any State thereof,
         or any bankruptcy or similar proceedings shall be filed involuntarily
         against Tenant thereunder.

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                  (d) A receiver or trustee shall be appointed for all or
         substantially all of the assets of Tenant.

                  (e) Tenant shall desert or vacate any substantial portion of
         the premises.

                  (f) Tenant shall fail to comply with any term, provision, or
         covenant of this lease (other than the foregoing in this Paragraph 16),
         and shall not cure such failure within thirty (30) days after written
         notice thereof to Tenant (or such longer period as is reasonably
         necessary to cure such failure, provided that Tenant shall commence the
         cure of such failure within such thirty (30) day period and shall
         continuously and diligently pursue the remedy of such failure).

         17. Remedies. Upon the occurrence of any of such events of default
described in Paragraph 16 hereof, Landlord shall have the option to pursue any
one or more of the following remedies without any notice or demand whatsoever:

                  (a) Terminate this lease, in which event Tenant shall
         immediately surrender the premises to Landlord, and if Tenant fails so
         to do, Landlord may, without prejudice to any other remedy which it may
         have for possession or arrearages in rent, enter upon and take
         possession of the premises and expel or remove Tenant and any other
         person who may be occupying such premises or any part thereof, by force
         if necessary, without being liable for prosecution or any claim or
         damages therefor; and Tenant agrees to pay to Landlord on demand the
         amount of any loss and damage which Landlord may suffer by reason of
         such termination, whether through inability to relet the premises on
         satisfactory terms or otherwise.

                  (b) Enter upon and take possession of the premises and expel
         or remove Tenant and any other person who may be occupying such
         premises or any part thereof, by force if necessary, without being
         liable for prosecution or any claim for damages therefor, and relet the
         premises and receive the rent therefor; and Tenant agrees to pay to the
         Landlord on demand any deficiency that may arise by reason of such
         reletting. In the event Landlord is successful in reletting the
         premises at a rental in excess of that agreed to be paid by Tenant
         pursuant to the terms of this Agreement, Landlord and Tenant each
         mutually agree that Tenant shall not be entitled, under any
         circumstances, to such excess rental, and Tenant does hereby
         specifically waive any claim to such excess rental.

                  (c) Enter upon the premises, by force if necessary, without
         being liable for prosecution or any claim for damages therefor, and do
         whatever Tenant is obligated to do under the terms of this lease; and
         Tenant agrees to reimburse Landlord, on demand, for any expenses which
         Landlord may incur in thus effecting compliance with Tenant's
         obligations under this lease, and Tenant further agrees that Landlord
         shall not be liable for any damages resulting to the Tenant from such
         action, whether caused by the negligence of the Landlord or otherwise.

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         Pursuit of any of the foregoing remedies shall not preclude pursuit of
any of the other remedies herein provided or any other remedies provided by law,
nor shall pursuit of any remedy herein provided constitute a forfeiture or
waiver of any rent due to Landlord hereunder or of any damages accruing to
Landlord by reason of the violation of any of the terms, provisions and
covenants herein contained. No act or thing done by the Landlord or its agents
during the term hereby granted shall be deemed a termination of this lease or an
acceptance of the surrender of the premises, and no agreement to terminate this
lease or to accept a surrender of said premises shall be valid unless in writing
signed by Landlord. No waiver by Landlord or any violation or breach of any of
the terms, provisions and covenants herein contained shall be deemed or
construed to constitute a waiver of any other violation or breach of any of the
terms, provisions and covenants herein contained. Forbearance by Landlord to
enforce one or more of the remedies herein provided upon an event of default
shall not be deemed or construed to constitute a waiver of such default or of
Landlord's right to enforce any such remedies with respect to such default or
any subsequent default. If on account of any breach or default by Tenant in
Tenant's obligations under the terms and conditions of this lease, it shall
become necessary or appropriate for Landlord to employ or consult with an
attorney concerning or to enforce or defend any of Landlord's rights or remedies
hereunder, Tenant agrees to pay any attorneys' fees so incurred by Landlord.

         18. No Landlord's Lien. Landlord hereby waives any landlord's lien or
similar lien for rent, whether the same arises by statute or common law.

         19. Mortgages. Tenant accepts this lease subject and subordinate to any
mortgage(s) and/or deed(s) of trust now or at any time hereafter constituting a
lien or charge upon the premises or the improvements situated thereon; provided,
however, that if the mortgagee, trustee, or holder of any such mortgage or deed
of trust elects to have Tenant's interest in this lease superior to any such
instrument, then by notice to Tenant from such mortgagee, trustee or holder,
this lease shall be deemed superior to such lien, whether this lease was
executed before or after said mortgage or deed of trust. Tenant shall at any
time hereafter, on demand, execute any instruments, releases or other documents
which may be required by any mortgagee for the purpose of subjecting and
subordinating this lease to the lien of any such mortgage.

         20. Mechanic's Liens. Tenant shall have no authority, express or
implied, to create or place any lien or encumbrance, of any kind or nature
whatsoever upon, or in any manner to bind, the interest of Landlord in the
premises or to charge the rentals payable hereunder for any claim in favor of
any person dealing with Tenant, including those who may furnish materials or
perform labor for any construction or repairs, and each such claim shall affect
and each such lien shall attach to, if at all, only the leasehold interest
granted to Tenant by this instrument. Tenant covenants and agrees that it will
pay or cause to be paid all sums legally due and payable by it on account of any
labor performed or materials furnished in connection with any work performed on
the premises on which any lien is or can be validly and legally asserted against
its leasehold interest in the premises or the improvements thereon and that it
will save and hold Landlord harmless from any and all loss, cost or expense
based on or arising out of asserted claims or liens

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against the leasehold estate or against the right, title and interest of the
Landlord in the premises or under the terms of this lease.

         21. Notices. Each provision of this instrument or of any applicable
governmental laws, ordinances, regulations and other requirements with reference
to the sending, mailing or delivery of any notice or the making of any payment
by Landlord to Tenant or with reference to the sending, mailing, or delivery of
any notice or the making of any payment by Tenant to Landlord shall be deemed to
be complied with when and if the following steps are taken:

                  (a) All rent and other payments required to be made by Tenant
         to Landlord hereunder shall be payable to Landlord at the address
         hereinbelow set forth or at such other address as Landlord may specify
         from time to time by written notice delivered in accordance herewith.
         Tenant's obligation to pay rent and any other amounts to Landlord under
         the terms of this lease shall not be deemed satisfied until such rent
         and other amounts have been actually received by Landlord.

                  (b) All payment required to be made by Landlord to Tenant
         hereunder shall be payable to Tenant at the address hereinbelow set
         forth, or at such other address within the continental United States as
         Tenant may specify from time to time by written notice delivered in
         accordance herewith.

                  (c) Any notice or document required or permitted to be
         delivered hereunder shall be deemed to be delivered whether actually
         received or not when deposited in the United States Mail, postage
         prepaid, Certified or Registered Mail, addressed to the parties hereto
         at the respective addresses set out below, or at such other address as
         they have theretofore specified by written notice delivered in
         accordance herewith:

               LANDLORD:                                TENANT:
                                                
         Whitson Properties, L.C.                    Span Instruments, Inc.
         1947 Avenue K                               1947 Avenue K
         Plano, Texas 75074                          Plano, Texas 75074
                                             
         If and when included within the term "Landlord", as used in this
instrument, there are more than one person, firm or corporation, all shall
jointly arrange among themselves for their joint execution of such a notice
specifying some individual at some specific address for the receipt of notices
and payments to Landlord; if and when included within the term "Tenant", as used
in this instrument, there are more than one person, firm or corporation, all
shall jointly arrange among themselves for their joint execution of such a
notice specifying some individual at some specific address within the
continental United States for the receipt of notices and payments to Tenant. All
parties included within the terms "Landlord" and "Tenant", respectively, shall
be bound by notices given in accordance with the provisions of this paragraph to
the same effect as if each had received such notice.

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         22.      Miscellaneous.

         A. Words of any gender used in this lease shall be held and construed
to include any other gender, and words in the singular number shall be held to
include the plural, unless the context otherwise requires.

         B. The terms, provisions, covenants, and conditions contained in this
lease shall apply to, inure to the benefit of, and be binding upon, the parties
hereto and upon their respective heirs, legal representatives, successors and
permitted assigns except as otherwise herein expressly provided. Each party
agrees to furnish the other, promptly upon demand, a corporate resolution, proof
of due authorization by partners, or other appropriate documentation evidencing
the due authorization of such party to enter into this lease.

         C. The captions inserted in this lease are for convenience only and in
no way define, limit or otherwise describe the scope or intent of this lease, or
any provision hereof, or in any way affect the interpretation of this lease.

         D. Tenant agrees from time to time within ten (10) days after request
of Landlord, to deliver to Landlord, or Landlord's designee, an estoppel
certificate stating that this lease is in full force and effect, the date to
which rent has been paid, the unexpired term of this lease and such other
matters pertaining to this lease as may be reasonably requested by Landlord. It
is understood and agreed that Tenant's obligation to furnish such estoppel
certificates in a timely fashion is a material inducement for Landlord's
execution of this lease.

         E. This lease may not be altered, changed or amended except by an
instrument in writing signed by both parties hereto.

         F. All obligations of Tenant hereunder not fully performed as of the
expiration or earlier termination of the term of this lease shall survive the
expiration of earlier termination of the term hereof, including without
limitation all payment obligations with respect to taxes and insurance and all
obligations concerning the condition of the premises. Upon the expiration or
earlier termination of the term hereof, and prior to Tenant vacating the
premises, Tenant shall pay to Landlord any amount reasonably estimated by
Landlord as necessary to put the premises, including without limitation all
heating and air conditioning systems and equipment therein, in good condition
and repair. Tenant shall also, prior to vacating the premises, pay to Landlord
the amount, as estimated by Landlord, of Tenant's obligation hereunder for real
estate taxes and insurance premiums for the year in which the lease expires or
terminates. All such amounts shall be used and held by Landlord for payment of
such obligations of Tenant hereunder, with Tenant being liable for any
additional costs therefor upon demand by Landlord, or with any excess to be
returned to Tenant after all such obligations have been determined and
satisfied, as the case may be. Any security deposit held by Landlord shall be
credited against the amount payable by Tenant under this subparagraph 22F.

                                      -11-
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         G. If any clause or provision of this lease is illegal, invalid or
unenforceable under present or future laws effective during the term of this
lease, then and in that event, it is the intention of the parties hereto that
the remainder of this lease shall not be affected thereby, and it is also the
intention of the parties of this lease that in lieu of each clause or provision
of this lease that is illegal, invalid or unenforceable, there be added as a
part of this lease contract a clause or provision as similar in terms to such
illegal, invalid or unenforceable clause or provision as may be possible and be
legal, valid and enforceable.

         H. All references in this lease to "the date hereof" or similar
references shall be deemed to refer to the last date, in point of time, on which
all parties hereto have executed this lease.

         EXECUTED this 14th day of June, 1996 to be EFFECTIVE as of March 1,
1996.

                                    LANDLORD:

                                                  WHITSON PROPERTIES, L.C.


                                                  By: /s/ Don E. Whitson
                                                      --------------------------
                                                  Name (print): Don E. Whitson
                                                               -----------------
                                                  Title: President
                                                        ------------------------

                                                  TENANT:

                                                  SPAN INSTRUMENTS, INC.


                                                  By: /s/ Brian Day
                                                      --------------------------
                                                  Name (print): Brian Day
                                                               -----------------
                                                  Title: Chief Financial Officer
                                                        ------------------------


Exhibits:

Exhibit "A" - Description of Premises


                                      -12-
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                                   Exhibit "A"

                             Description of Premises

TRACT I:

BEING located at 2205 Avenue K, being part of Lot 1, Block 1 of Apple Square
Revised Addition, an addition to the City of Plano, Texas, according to the plat
recorded in Volume F, Page 233, Map Records Collin County, Texas, and being more
particularly described as follows:

BEGINNING at the intersection of the West line of Avenue K, (a 100' R.O.W.),
with the North line of 22nd Street, (a 40' R.O.W.), said point being the
Southeast corner of said Lot 1, an "x" cut in concrete for corner;

THENCE: West, with the said North line of 22nd Street, a distance of 181.10
feet, a 1/2" iron rod set for corner;

THENCE: North 00 deg. 29 min. 12 sec. East, a distance of 133.00 feet, an "x"
cut in concrete for corner;

THENCE: East, a distance of 181.10 feet to a point in the said West line of
Avenue K, a p.k. nail set for corner;

THENCE: South 00 deg. 29 min. 12 sec. West, with the said West line of Avenue K,
a distance of 133.00 feet to the PLACE OF BEGINNING and CONTAINING 24,085 square
feet or 0.553 acres of land.

TRACT II:

The property/building located at 1007 20th Street, Plano, Texas, commonly
referred to as the South Building and the property located on the south side of
the street across from 1007 20th Street, Plano, Texas.

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