<PAGE>
                                                            Exhibit 10.18
                                  OFFICE LEASE



                                HAMILTON LANDING
                            NOVATO, CALIFORNIA 94949

      Landlord:

                              HAMILTON MARIN, LLC,
                     a California limited liability company



                                       and

      Tenant:

                               SPATIALIGHT, INC.,
                             a New York corporation

                               Dated: May 17, 2002


<PAGE>

                                HAMILTON LANDING

                       SUMMARY OF BASIC LEASE INFORMATION

            The undersigned hereby agree to the following terms of this Summary
of Basic Lease Information (the "Summary"). This Summary is hereby incorporated
into and made a part of the attached Office Lease ("Office Lease") (this Summary
and the Office Lease to be known collectively as the "Lease") which pertains to
the "Project" (as that term is defined in the Office Lease) located at Hangar 5,
Five Hamilton Landing, Novato, California 94949. Each reference in the Office
Lease to any term of this Summary shall have the meaning as set forth in this
Summary for such term. In the event of a conflict between the terms of this
Summary and the Office Lease, the terms of the Office Lease shall prevail. Any
capitalized terms used herein and not otherwise defined herein shall have the
meaning as set forth in the Office Lease.

<TABLE>
<CAPTION>
      TERMS OF LEASE                                     DESCRIPTION
      --------------                                     -----------
      (References are to the Office Lease)
<S>                                                      <C>
1.    Date:                                              May 17, 2002

2.    Landlord:                                          Hamilton Marin, LLC, a California limited liability company

3.    Address of Landlord:                               c/o Barker Pacific Group, Inc.
      (Section 20.28)                                    Three Hamilton Landing Suite 200
                                                         Novato, California 94949
                                                         Attention:  Richard J. Johnson

4.    Tenant:                                            SPATIALIGHT, INC., a New York corporation

5.    Address of Tenant;                                 Prior to Lease Commencement Date:
      (Section 20.28)

                                                         9 Commercial Boulevard, Suite 200
                                                         Novato, California  94949
                                                         Attention:  Steve Tripp

                                                         Following Lease Commencement Date:
                                                         Hangar 5, Suite 100
                                                         Five Hamilton Landing
                                                         Novato, California 94949
                                                         Attention:  Steve Tripp

6.    Building; Premises
      (Article 1):

      6.1   Building:                                    Approximately 54,097 square feet of Rentable Area
                                                         Hangar 5
                                                         Five Hamilton Landing
                                                         Novato, California  94949

      6.2   Premises:                                    Approximately 13,541 square feet of Rentable Area located on the
                                                         first floor of the Building as set forth in Exhibit A attached
                                                         hereto.

7.    Term (Article 3):

      7.1   Lease Term:                                  Seventy-two (72) months.
</TABLE>


<PAGE>

<TABLE>
<S>                                                      <C>
      7.2   Lease Commencement Date:                     The earlier of (i) the date Tenant commences business in the
                                                         Premises, and (ii) the date of Substantial Completion (as
                                                         defined in Section 6 of Exhibit C attached to the Office Lease)
                                                         of the Tenant Improvements by Landlord (subject to acceleration
                                                         pursuant to Section 6 of Exhibit C attached to the Office Lease).

      7.3   Lease Expiration Date:                       The last day of the calendar month in which the 72nd month
                                                         anniversary of the Lease Commencement Date occurs.

8.    Base Rent (Article 4):
</TABLE>

<TABLE>
<CAPTION>
                                             Monthly Installment         Monthly Rental Rate per
     Months            Annual Base Rent          of Base Rent         Square Foot of Rentable Area
     ------            ----------------      -------------------      ----------------------------
<S>                    <C>                   <C>                      <C>
01-12                    $203,115.00              $16,926.25                      $1.25
13-24                    $418,416.96              $34,868.08                      $2.575
25-36                    $430,603.80              $35,883.65                      $2.65
37-48                    $442,790.76              $36,899.23                      $2.725
49-60                    $454,977.60              $37,914.80                      $2.80
61-Expiration of         $467,164.50              $38,930.38                      $2.875
Initial Term
</TABLE>

<TABLE>
<S>                                                      <C>
9.    Additional Rent (Article 4)

      9.1   Base Year                                    Calendar year 2002.

      9.2   Tenant's Percentage Share:                   Approximately 25.837%.

10.   Security Deposit (Article 4):                      $33,405.00.

11.   Parking Passes (Section 20.18):                    Three and six-tenths (3.6) unreserved parking passes
                                                         non-designated parking spaces per each one thousand (1,000)
                                                         square feet of Rentable Area within the Premises (rounding to
                                                         the nearest whole number of parking spaces in the event the
                                                         Rentable Area of the Premises is not evenly divisible by one
                                                         thousand (1,000)), which parking spaces shall be located within
                                                         the unreserved common parking areas of the Project, without
                                                         charge during the Term.

12.   Brokers (Section 20.15):                           Orion Partners, as Landlord's Agent, and Orion Partners, as
                                                         Tenant's Agent

13.   Use:                                               General office use and use as a laboratory for high definition
                                                         television technology.
</TABLE>

      The foregoing terms of this Summary are hereby agreed to by Landlord and
      Tenant.


<PAGE>

"LANDLORD":

HAMILTON MARIN, LLC,
a California limited liability company

By:   Barker Pacific Group, Inc.,
      a Delaware corporation,
      its Authorized Signatory


      By:/s/ MICHAEL D. BARKER
         -------------------------------
              Michael D. Barker,
              Managing Director

"TENANT":

SPATIALIGHT, INC., a New York corporation


By: /s/ ROBERT A. OLINS
    ----------------------------------------

Print Name: Robert A. Olins
            --------------------------------

Its: Chief Executive Officer
     ---------------------------------------

By:
    ----------------------------------------

Print Name:
            --------------------------------

Its:
     ---------------------------------------


<PAGE>

                                HAMILTON LANDING

                                  OFFICE LEASE

                                TABLE OF CONTENTS

<TABLE>
<CAPTION>
                                                                                         Page
<S>                                                                                      <C>
ARTICLE 1 PROJECT, BUILDING AND PREMISES..............................................     4

      1.1       Project, Building and Premises........................................     4
      1.2       Condition of the Premises.............................................     4
      1.3       Common Areas..........................................................     4
      1.4       Landlord's Reserved Rights in Premises and Common Areas...............     5
      1.5       Rentable Area.........................................................     5
      1.6       Tenant's Percentage Share.............................................     5

ARTICLE 2 PLANS AND CONSTRUCTION......................................................     5

ARTICLE 3 TERM; USE; COMPLIANCE WITH LAWS.............................................     6

      3.1       Commencement of Term..................................................     6
      3.2       General Use and Compliance with Laws..................................     6
      3.3       Extension Option......................................................     6

ARTICLE 4 RENT........................................................................     8

      4.1       Rent..................................................................     8
      4.2       Rent Adjustment.......................................................     8
      4.3       Definitions...........................................................     9
      4.4       Operating Expenses....................................................    10
      4.5       Monthly Rent Payments.................................................    12
      4.6       Additional Rent.......................................................    12
      4.7       No Deduction or Offset................................................    12
      4.8       Late Payment and Interest.............................................    12
      4.9       Security Deposit......................................................    13

ARTICLE 5 SERVICES AND UTILITIES......................................................    13

      5.1       Basic Services........................................................    13
      5.2       Over Standard Use.....................................................    14
      5.3       Interruption of Use...................................................    14
      5.4       Additional Services...................................................    14
      5.5       Keys and Locks........................................................    14
      5.6       Clean Room Electrical Costs...........................................    15

ARTICLE 6 REPAIRS.....................................................................    15

      6.1       Tenant's Repairs......................................................    15
      6.2       Landlord's Repairs....................................................    15
      6.3       Entry.................................................................    16

ARTICLE 7 ALTERATIONS.................................................................    16

      7.1       Landlord's Consent to Alterations.....................................    16
      7.2       Manner of Construction................................................    16
      7.3       Payment for Improvements..............................................    17
      7.4       Landlord's Property and Fixtures......................................    17
</TABLE>


                                      -1-
<PAGE>

<TABLE>
<S>                                                                                       <C>
ARTICLE 8 COVENANT AGAINST LIENS......................................................    17

ARTICLE 9 INSURANCE...................................................................    18

      9.1       Landlord Coverage:  All Risk..........................................    18
      9.2       Tenant Coverage.......................................................    18
      9.3       General Insurance Requirements........................................    19
      9.4       Indemnification and Waiver............................................    19

ARTICLE 10 DAMAGE AND DESTRUCTION.....................................................    20

      10.1      Repair of Damage to Premises by Landlord..............................    20
      10.2      Landlord's Option to Repair...........................................    20
      10.3      Waiver of Statutory Provisions........................................    21

ARTICLE 11 NON-WAIVER.................................................................    21

ARTICLE 12 EMINENT DOMAIN.............................................................    21

      12.1      Taking................................................................    21
      12.2      Temporary Taking......................................................    22
      12.3      Total Taking..........................................................    22

ARTICLE 13 ASSIGNMENT AND SUBLETTING..................................................    22

      13.1      Transfers.............................................................    22
      13.2      Landlord's Consent....................................................    22
      13.3      Landlord's Option as to Subject Space.................................    23
      13.4      Transfer Premium......................................................    23
      13.5      Effect of Transfer....................................................    23
      13.6      Additional Transfers..................................................    24
      13.7      Affiliate Transfers...................................................    24

ARTICLE 14 SURRENDER OF PREMISES; TRADE FIXTURES......................................    24

      14.1      Surrender of Premises.................................................    24
      14.2      Removal of Tenant Property by Tenant..................................    24

ARTICLE 15 HOLDING OVER...............................................................    25

ARTICLE 16 ESTOPPEL, SUBORDINATION AND ATTORNMENT.....................................    25

      16.1      Estoppel Certificate..................................................    25
      16.2      Subordination.........................................................    25

ARTICLE 17 DEFAULTS; REMEDIES.........................................................    26

      17.1      Events of Default.....................................................    26
      17.2      Landlord's Remedies...................................................    27
      17.3      No Waiver.............................................................    28

ARTICLE 18 GRAPHICS...................................................................    28

      18.1      General...............................................................    28
      18.2      Building Directory....................................................    28
      18.3      Prohibited Signage and Other Items....................................    28
</TABLE>


                                      -2-
<PAGE>

<TABLE>
<S>                                                                                       <C>
ARTICLE 19 LANDLORD'S RIGHT TO CURE DEFAULT; PAYMENTS BY TENANT.......................    28

      19.1      Landlord's Cure.......................................................    28
      19.2      Tenant's Reimbursement................................................    29

ARTICLE 20 MISCELLANEOUS PROVISIONS...................................................    29

      20.1      Terms.................................................................    29
      20.2      Binding Effect........................................................    29
      20.3      Easements.............................................................    29
      20.4      No Light, Air or View Easement........................................    29
      20.5      Authorization.........................................................    29
      20.6      Accord and Satisfaction...............................................    29
      20.7      Peaceful Enjoyment....................................................    29
      20.8      Limitation of Landlord's Liability....................................    30
      20.9      Time, Calendar Year; Calendar Days....................................    30
      20.10     Severability..........................................................    30
      20.11     Applicable Law........................................................    30
      20.12     Submission of Lease...................................................    30
      20.13     Rules and Regulations.................................................    30
      20.14     No Nuisance...........................................................    30
      20.15     Broker................................................................    30
      20.16     Modification for Lender...............................................    31
      20.17     Recording.............................................................    31
      20.18     Parking Facilities....................................................    31
      20.19     No Merger.............................................................    31
      20.20     Amendment.............................................................    31
      20.21     Financial Statements..................................................    31
      20.22     Hazardous Substances; Indemnification.................................    32
      20.23     Entire Agreement......................................................    32
      20.24     Force Majeure.........................................................    33
      20.25     Waiver of Redemption..................................................    33
      20.26     Joint and Several.....................................................    33
      20.27     Notices...............................................................    33
      20.28     Attorneys' Fees.......................................................    33
      20.29     Independent Covenants.................................................    33
      20.30     Project Name and Signage..............................................    34
      20.31     Transportation Management.............................................    34
      20.32     No Discrimination.....................................................    34
</TABLE>


                                      -3-
<PAGE>

                                HAMILTON LANDING

                                  OFFICE LEASE

      This Office Lease, which includes the preceding Summary of Basic Lease
Information (the "Summary") attached hereto and incorporated herein by this
reference (the Office Lease and Summary to be known sometimes collectively
hereafter as the "Lease"), dated as of the date set forth in Article 1 of the
Summary, is made by and between Hamilton Marin, LLC, a California limited
liability company ("Landlord"), and SPATIALIGHT, INC., a New York corporation
("Tenant").

                                    ARTICLE 1

                         PROJECT, BUILDING AND PREMISES

      1.1 Project, Building and Premises. Upon and subject to the terms,
covenants and conditions hereinafter set forth in this Lease, Landlord hereby
leases to Tenant and Tenant hereby leases from Landlord the premises set forth
in Article 6 of the Summary (the "Premises"), which Premises are located in the
"Project" (as that term is defined in this Section 1.1). The outline of the
floor plan of the Premises is set forth in Exhibit A attached hereto and made a
part hereof. The Premises are a part of Project commonly known as "Hamilton
Landing", in Novato, California 94949. The land on which such Project is located
is more particularly described in Exhibit B attached hereto and made a part
hereof. The building in which the Premises is located (the "Building"), the
other buildings within Hamilton Landing, the land and other improvements
surrounding the Building and such other buildings which are designated from time
to time by Landlord as common areas appurtenant to or servicing the Building and
such other buildings, and the land upon which any of the foregoing are situated,
are herein sometimes collectively referred to as the "Project." Tenant is hereby
granted the right to the nonexclusive use of (a) the common corridors and
hallways, stairwells, elevators, restrooms within the Building, and (b) the
other public or common areas located within the Project outside of the buildings
therein; provided, however, that the manner in which such public and common
areas are maintained and operated shall be at the sole discretion of Landlord
and the use thereof shall be subject to such rules, regulations and restrictions
as Landlord may make from time to time. Landlord reserves the right to make
alterations or additions to or to change the location of elements of the Project
and the common areas thereof. Except when and where Tenant's right of access is
specifically excluded in this Lease, Tenant shall have the right of access to
the Premises twenty-four (24) hours per day, seven (7) days per week during the
Lease Term.

      1.2 Condition of the Premises. Except as specifically set forth in this
Lease and in the Work Letter attached hereto as Exhibit C and made a part hereof
(the "Work Letter"), Landlord shall not be obligated to provide or pay for any
improvement work or services related to the improvement of the Premises. Tenant
also acknowledges that Landlord has made no representation or warranty regarding
the condition of the Premises or the Project except as specifically set forth in
this Lease and the Work Letter.

      1.3 Common Areas. Appurtenant to the Premises and subject to reasonable
and non-discriminatory rules and regulations from time to time made by Landlord
of which Tenant is given notice, Tenant shall have the right to the use of the
following common areas ("Project Common Areas"):

            (a) Building Common Area. The common stairways, corridors and
      accessways, vending or mail areas, lobbies and foyers, entrances, stairs,
      elevators, restrooms, janitorial, telephone, mechanical and electrical
      rooms and any passageways thereto, and the common pipes, ducts, conduits,
      wires and appurtenant equipment serving the Premises.

            (b) Land Common Area. The common walkways and sidewalks necessary
      for access to the Project and the outdoor courtyards. Tenant's acceptance
      of the Premises shall constitute an acknowledgment and acceptance of the
      various temporary inconveniences that may be associated with the use of
      the Project Common Areas.


                                      -4-
<PAGE>

            (c) Parking. Tenant is hereby granted the right to use three and
      one-half (3.5) non-designated parking spaces per each one thousand (1,000)
      square feet of Rentable Area within the Premises (rounding to the nearest
      whole number of parking spaces in the event the Rentable Area of the
      Premises is not evenly divisible by one thousand (1,000)), which parking
      spaces shall be located within the unreserved common parking areas of the
      Project, all in accordance with Section 20.18 below.

            (d) Declaration. On or before the Lease Commencement Date, Landlord
      shall record against the entire Project a Declaration and Establishment of
      Protective Covenants, Conditions and Restrictions and Grant of Easements
      (the "Declaration"). Among other provisions, the Declaration will provide
      for the operation, repair and maintenance of the Land Common Area and the
      allocation of the cost of the operation, repair and maintenance of the
      Land Common Area among the owners of the various parcels that comprise the
      Project.

      1.4 Landlord's Reserved Rights in Premises and Common Areas. Landlord
reserves the right from time to time:

            (a) Building Changes. To install, use, maintain, repair and replace
      pipes, ducts, conduits, wires and appurtenant meters and equipment for
      service to other parts of the Building above the ceiling surfaces, below
      the floor surfaces, within the walls and in the central core areas, and to
      relocate any pipes, ducts, conduits, wires and appurtenant meters and
      equipment in the Premises which are so located or located elsewhere
      outside the Premises.

            (b) Boundary Changes. To change the lines of the lot on which the
      Building stands (the "Lot") and to make other reasonable changes and grant
      others rights thereto, including without limitation the granting of
      easements, rights of way and rights of ingress and egress and similar
      rights to users of parcels adjacent to the Lot.

            (c) Facility Changes. To alter or relocate any other common areas or
      facilities associated with the Project.

      1.5 Rentable Area. As used in this Lease, the term "Rentable Area" shall
mean one hundred fifteen percent (115%) of the "Usable Area." As used in this
Lease, "Usable Area" shall be measured in accordance with BOMA standards
(Building Owners and Managers Association Method for Measuring Floor Area in
Office Buildings, ANSI Z65.1-1996).

      The Rentable Area of the Premises and the Rentable Area of the Building
have been calculated on the basis of the foregoing definition and, subject to
the provisions of Section 1.6, are hereby stipulated for all purposes hereof to
be the amounts stated in the Summary, subject to confirmation by actual
measurement by Landlord's architect, at Landlord's cost, prior to Tenant's
occupancy.

      1.6 Tenant's Percentage Share. The term "Tenant's Percentage Share" shall
mean the percentage figure specified in the Summary which represents the ratio
that the Rentable Area of the Premises bears to one hundred percent (100%) of
the Rentable Area of the Building. In the event Tenant's Percentage Share is
changed during a calendar year by reason of a change in the Rentable Area of the
Premises or a change in the total Rentable Area of the Building or leased
portion thereof, Tenant's Percentage Share shall be re-calculated pursuant to
the aforementioned formula and shall be determined on the basis of the number of
days during such calendar year at each such percentage.

                                    ARTICLE 2
                             PLANS AND CONSTRUCTION

      The design and construction of, and payment for, the "Tenant Improvements"
(as defined in the Work Letter) shall be governed by the provisions of the Work
Letter.


                                      -5-
<PAGE>

                                    ARTICLE 3
                         TERM; USE; COMPLIANCE WITH LAWS

      3.1 Commencement of Term. Subject to and upon the terms and conditions set
forth in this Lease, the term of this Lease shall be for a period specified in
the Summary as Lease Term, commencing upon the date specified in the Summary as
the Lease Commencement Date. Upon the Lease Commencement Date, Landlord and
Tenant shall execute a Notice of Lease Term Dates, as shown in Exhibit E
attached hereto and made a part hereof setting forth, among other things, the
Lease Commencement Date and the Lease Expiration Date.

      3.2 General Use and Compliance with Laws. Tenant shall only use the
Premises for general office purposes and use as a laboratory for high definition
television technology and for processing of materials in connection with liquid
crystal displays, in each case in compliance with, and subject to, applicable
Governmental Requirements, and for no other use. At Tenant's sole cost and
expense, Tenant shall comply with and faithfully observe all of the requirements
of municipal, county, state, federal and other applicable governmental
authorities (collectively, "Governmental Requirements"), now in force, or which
may hereafter be in force, pertaining to the use and occupancy of the Premises,
Lot and Project (including, without limitation, the Americans with Disabilities
act of 1990 and any other Governmental Requirements respecting accessibility or
use by disabled persons) and shall secure any necessary permits pertaining to
Tenant's use and occupancy of the Premises. Without limiting the generality of
the foregoing, Tenant, at Tenant's sole cost, shall be solely responsible for
making any alterations or improvements to the Premises required to cause the
Premises to comply with applicable Governmental Requirements, except that if
such alterations or improvements are of a structural nature, then Landlord (and
not Tenant) shall be responsible for making such required alterations or
improvements (the cost of which shall be included in Operating Expenses), except
to the extent such alterations or improvements are required as a result of
Tenant's particular use of, or alterations or improvements to, the Premises. In
Tenant's use and occupancy of the Premises, Tenant shall not subject the
Premises to any use that would tend to damage any portion thereof or which shall
in any way increase the existing rate of any insurance on the Project or any
portion thereof or cause any cancellation of any insurance policy covering the
Project or any portion thereof; provided that Tenant may use the Permitted
Hazardous Substances (as defined in Section 20.22(c)) or the construction of the
Clean Room (as defined in Section 5.6). Tenant shall not do or permit anything
to be done in or about the Premises which shall in any way obstruct or interfere
with the rights of other tenants of the Project, or injure or annoy them, or use
or allow the Premises to be used for any improper, immoral, unlawful or
objectionable purpose, nor shall Tenant or Tenant's agents cause, maintain, or
permit any nuisance in, on or about the Premises or commit or suffer to be
committed any waste in, on or about the Premises. Except for normal office
equipment and furnishings, Tenant shall not bring into the Building, or keep or
arrange in the Premises any furniture, equipment, materials or other objects
which individually or collectively overload the Premises or the Building.
Landlord reserves the right to prescribe the weight and position of all safes,
fixtures and heavy installations that Tenant desires to place in the Premises so
as to distribute properly the weight, or to require plans prepared by a
qualified structural engineer for such heavy objects at Tenant's sole cost and
expense. Notwithstanding the foregoing, Landlord shall have no liability for
damage caused by the installation of such safes and heavy equipment.
Furthermore, business machines and mechanical equipment belonging to Tenant that
cause noise and/or vibration that may be transmitted to the structure of the
Building or to any other tenants in the Building shall be placed and maintained
by Tenant, at Tenant's sole cost and expense, in settings of cork, rubber or
spring type noise and/or vibration eliminators and Tenant shall take such other
measures directed by Landlord as needed to eliminate such vibration and/or
noise.

      3.3 Extension Option.

            (a) Option Right. Landlord hereby grants to Tenant one (1) option to
      extend the Lease Term for a period of five (5) years (the "Option Term"),
      which option shall be exercisable only by written notice delivered by
      Tenant to Landlord as provided below, provided that, as of the date of
      delivery of such notice, Tenant is not in default under this Lease beyond
      any applicable notice and cure periods. Upon the proper exercise of such
      option to extend, and provided that, as of the end of the initial Lease
      Term, Tenant is not in default under this Lease beyond any applicable
      notice and cure periods, the Lease Term as it applies to the Premises,
      shall be extended for the Option Term. The rights contained in this
      Section 3.3 shall be personal to the Original Tenant, and may only be
      exercised by the Original Tenant and not by any assignee or any sublessee
      or other transferee of Tenant's interest in this Lease or the Premises, or
      any part thereof.


                                      -6-
<PAGE>

            (b) Option Rent. The rent payable by Tenant during the Option Term
      (the "Option Rent") shall equal the "Fair Market Rental Rate" for the
      Premises. The term "Fair Market Rental Rate" for the Premises during the
      Option Term shall mean the annual amount per square foot of Rentable Area
      being charged on a full service basis by Landlord as of the first day of
      the Option Term for unencumbered, non-sublease, non-equity space
      comparable to the Premises in the Project or if not enough comparable
      transactions exist in the Project, then the annual amount per square foot
      of Rentable Area being charged on a full service basis for comparable
      space in "Comparable Buildings" (as that term is defined below), giving
      appropriate consideration to appropriate concessions ("Rent Concessions")
      and to all economic terms, such as annual rental rates per square foot of
      Rentable Area, escalation clauses (such as net, base year or expense
      stop), free rent, if any, length of the lease term, size and location of
      premises being leased and other generally acceptable terms and conditions
      for the tenancy of the space in question, including Tenant improvements or
      allowances provided or to be provided for such comparable space (provided,
      however, that the amount of such improvements or allowances shall be
      reduced when calculating the Option Rent by deducting the value of the
      existing improvements in the Premises, as of the first day of the Option
      Term, with such value to be based upon the age, quality and layout of the
      improvements); provided, however, in calculating the Fair Market Rental
      Rate, no consideration shall be given to the fact that (i) any rental
      abatement is or is not given such lessees in connection with the
      construction of improvements in such comparable space, or (ii) Landlord is
      or is not required to pay a real estate brokerage commission in connection
      with the Option Term, or the fact that comparable deals do or do not
      involve the payment of real estate brokerage commissions. If, in
      determining the Fair Market Rental Rent, Rent Concessions are granted
      Landlord may, at Landlord's sole option, elect any or a portion of the
      following: (1) to grant some or all of the Rent Concessions to Tenant in
      the form as described above (or as free rent and/or an improvement
      allowance); or (2) to adjust the rental rate component of the Fair Market
      Rental Rate to be an effective rental rate which takes into consideration
      the total dollar value of such Rent Concessions (in which case the Rent
      Concessions evidenced in the effective rental rate shall not be granted to
      Tenant). The term "Comparable Buildings", as used in this Lease, shall
      mean comparable office buildings located in central Marin County area.

            (c) Exercise of Option. The option to extend shall be exercised by
      Tenant, if at all, only in the following manner: (i) Tenant shall deliver
      written notice to Landlord not more than twelve (12) months nor less than
      eight (8) months prior to the expiration of the initial Lease Term,
      stating that Tenant may be interested in exercising its option; (ii)
      Landlord, within thirty (30) days after receipt of Tenant's notice, shall
      deliver notice (the "Option Rent Notice") to Tenant setting forth the
      Option Rent and, (iii) if Tenant wishes to exercise such option, Tenant
      shall, on or before the date occurring six (6) months prior to the
      expiration of the initial Lease Term, exercise such option by delivering
      written notice thereof to Landlord, and upon, and concurrent with, such
      exercise, Tenant may, at its option, object to the Option Rent contained
      in the Option Rent Notice, in which case the parties shall follow the
      procedure, and the Option Rent shall be determined, as set forth in
      Section 3.3(d) below.

            (d) Determination of Option Rent. In the event Tenant timely and
      appropriately objects in writing to the Option Rent initially determined
      by Landlord, Landlord and Tenant shall attempt to agree upon the Option
      Rent, using their best good-faith efforts. If Landlord and Tenant fail to
      reach agreement within twenty (20) days following Tenant's objection to
      the Option Rent (the "Outside Agreement Date"), then each party shall
      submit to the other party a separate written determination of the Option
      Rent within ten (10) business days after the Outside Agreement Date, and
      such determinations shall be submitted to arbitration in accordance with
      the provisions herein. Failure of Tenant or Landlord to submit a written
      determination of the Option Rent within such ten (10) business day period
      shall conclusively be deemed to be the non-determining party's approval of
      the Option Rent submitted within such ten (10) business day period by the
      other party.

            (e) Option Terms - Arbitration. Landlord and Tenant shall each
      appoint one arbitrator who shall by profession be a licensed real estate
      agent who shall have been active over the five (5) year period ending on
      the date of such appointment in the leasing of first-class office
      buildings in Marin County, California. The determination of the
      arbitrators shall be limited solely to the issue of whether Landlord's or
      Tenant's submitted Option Rent is the closest to the actual Option Rent as
      determined by the arbitrators, taking into account the requirements of
      Section 3.3(b) of this Lease with respect to the Option Rent. Each


                                      -7-
<PAGE>

      such arbitrator shall be appointed within thirty (30) days after the
      Outside Agreement Date and adopt procedures as follows: The two (2)
      arbitrators so appointed shall within ten (10) days of the date of the
      appointment of the last appointed arbitrator agree upon and appoint a
      third arbitrator who shall be qualified under the same criteria set forth
      hereinabove for qualification of the initial two (2) arbitrators. The
      three (3) arbitrators shall within thirty (30) days after the appointment
      of the third arbitrator reach a decision as to whether the panel shall use
      Landlord's or Tenant's submitted Option Rent and shall notify Landlord and
      Tenant thereof. The decision of the majority of the three (3) arbitrators
      shall be binding upon Landlord and Tenant. If either Landlord or Tenant
      fails to appoint an arbitrator within thirty (30) days after the
      applicable Outside Agreement Date, the arbitrator appointed by one of them
      shall reach a decision, notify Landlord and Tenant thereof, and such
      arbitrator's decision shall be binding upon Landlord and Tenant. If the
      two (2) arbitrators fail to agree upon and appoint a third arbitrator
      within the time period provided above, then the parties shall mutually
      select the third arbitrator. If Landlord and Tenant are unable to agree
      upon the third arbitrator within ten (10) days, then either party may,
      upon at least five (5) days prior written notice to the other party,
      request the Presiding Judge of the Marin County Superior Court, acting in
      his/her private and non-judicial capacity, to appoint the third
      arbitrator. Following the appointment of the third arbitrator, the panel
      of arbitrators shall within thirty (30) days thereafter reach a decision
      as to whether Landlord's or Tenant's submitted Option Rent shall be used
      and shall notify Landlord and Tenant thereof. The cost of the arbitrators
      and the arbitration proceeding shall be paid by Landlord and Tenant
      equally, except that each party shall pay for the cost of its own
      witnesses, agents and attorneys.

                                    ARTICLE 4
                                      RENT

      4.1 Rent. Tenant shall pay, without notice or demand, to Landlord at such
place as Landlord may from time to time designate in writing, in currency or a
check for currency which, at the time of payment, is legal tender for private or
public debts in the United States of America, "Base Rent" as set forth in
Article 8 of the Summary, payable in equal monthly installments in advance on or
before the first day of each and every month during the Lease Term, without any
set off or deduction whatsoever. Base Rent for the first full calendar month of
the Lease Term shall be paid to Landlord at the time of Tenant's execution of
this Lease. As used in this Lease, "Rent" shall collectively mean "Additional
Rent" (as defined in Section 4.6) together with the following sums:

            (a) Base Rent. The amount specified in the Summary as the Base Rent
      for the applicable portions of the Lease Term indicated, commencing on the
      Lease Commencement Date. The Base Rent includes a component applicable to
      "Operating Expenses" (defined in Section 4.4) per square foot of Rentable
      Area of office space in the Project. The scheduled Base Rent for the first
      twelve (12) months of the Term shown in Item 8 of the Summary of Basic
      Lease Information reflects an abatement of 50% given as an inducement to
      Tenant's entering into this Lease. Landlord and Tenant agree that for tax
      reporting purposes, none of the Base Rent due in periods in which Base
      Rent is not being abated shall be allocated to any other period.

            (b) Expense Rent. For each calendar year following the Base Year, an
      amount ("Expense Rent") equal to the Tenant's Percentage Share of the
      amount by which (A) the Building's Share of Operating Expenses for such
      calendar year, exceeds (B) the Building's Share of Operating Expenses for
      the Base Year. As used herein, the "Building's Share" of Operating
      Expenses shall mean all Operating Expenses attributable solely to the
      Building, and an equitable portion of the Operating Expenses attributable
      to the Project Common Areas or the Project as a whole; provided, however,
      that the basis for such allocation to each building of Operating Expenses
      attributable to Project Common Areas or the Project as a whole shall be
      the fraction of total Project Rentable Area included within such building
      unless Landlord in good faith determines that an alternate manner of
      allocation is more equitable.

      4.2 Rent Adjustment.

            (a) Base Rent Adjustment. The Base Rent adjustments for the Term are
      set forth in the Summary. If the Commencement Date is other than the first
      day of a calendar month, then for purposes of rent adjustments the number
      of months in the Term shall be measured from the first day of the calendar
      month in which the Commencement Date falls.


                                      -8-
<PAGE>

            (b) Expense Rent Adjustment. The amount to be paid initially as
      Expense Rent has been estimated by Landlord for the calendar year in which
      the Commencement Date occurs and is included in the Base Rent. Commencing
      with the calendar year following the Base Year and continuing each year
      thereafter, Tenant's payment of Expense Rent shall be estimated and
      adjusted in accordance with the following procedures and the provisions of
      Section 4.5.

                        (i) Prior to the commencement of each calendar year
            following the Base Year, or as soon thereafter as practicable,
            Landlord shall give Tenant written notice of its estimate of Expense
            Rent for the ensuing twelve (12) month period; provided that if such
            notice is not given at least twenty (20) days prior to the
            commencement of the calendar year, Tenant shall continue to pay on
            the basis of the then applicable Expense Rent until the month after
            such notice is given, at which time Tenant shall pay Expense Rent
            based on the amount set forth in such notice plus, if the new
            Expense Rent is greater than the previous Expense Rent, the
            difference accrued from January 1 of such calendar year. If the new
            Expense Rent is less than the previous Expense Rent, the difference
            accrued from January 1 of such calendar year shall be credited
            against Expense Rent next coming due under this Lease.

                        (ii) Within ninety (90) days after the close of each
            calendar year or as soon thereafter as possible, Landlord shall
            deliver to Tenant a statement (the "Statement") setting forth the
            amount of Expense Rent for that calendar year. If the Expense Rent
            estimates paid by Tenant for such calendar year are less than the
            actual Expense Rent for such calendar year, Tenant shall pay the
            difference to Landlord within thirty (30) days of the delivery of
            the Statement. If the Expense Rent estimates paid by Tenant for such
            calendar year are greater than the actual Expense Rent for such
            calendar year, Landlord shall credit such difference against Expense
            Rent next coming due under this Lease.

            (c) Inspection of Records. If Tenant disputes the amount of Expense
      Rent stated in the Statement, Tenant may designate in writing, within
      thirty (30) days after receipt of that Statement, an independent certified
      public accountant acceptable to Landlord to inspect Landlord's records.
      Tenant is not entitled to request that inspection, however, if Tenant is
      then in default under this Lease. Tenant's inspection shall be limited
      strictly to those items in the Statement that Tenant has specifically
      identified in writing as being allegedly incorrect. Tenant shall not be
      entitled to inspect any of Landlord's books and records that apply to any
      prior Statements or to any calendar year other than the year covered by
      the most recent Statement. The accountant must be a member of a nationally
      recognized accounting firm and must not charge a fee based on the amount
      of Expense Rent that the accountant is able to save Tenant by the
      inspection. Tenant shall be entitled to no more than one (1) inspection
      per calendar year. No subtenant has any right to conduct an inspection and
      no assignee shall conduct an inspection for any period during which such
      assignee was not in possession of the Premises. Tenant's designation of
      its accountant shall specify a date for the inspection which shall be no
      later than thirty (30) days after the date Tenant designates its
      accountant. The inspection must be conducted in Landlord's offices (or, if
      Landlord so directs, at another location at which the books and records
      for the Building are located) at a reasonable time or times. If, after
      that inspection, Tenant still disputes the Expense Rent, a certification
      of the proper amount shall be made, at Tenant's expense, by Landlord's
      independent certified public accountant. That certification shall be final
      and conclusive. As a condition precedent to any inspection by Tenant's
      accountant, Tenant shall deliver to Landlord a copy of Tenant's written
      agreement with such accountant, which agreement shall include provisions
      which state that (i) Landlord is an intended third party beneficiary of
      such agreement, (ii) such accountant will not in any manner solicit or
      agree to represent any other tenant of the Project with respect to an
      audit or other review of Landlord's accounting records at the Project, and
      (iii) such accountant shall maintain in strict confidence any and all
      information obtained in connection with the review and shall not disclose
      such information to any person or entity other than to the management
      personnel of Tenant. An overcharge of Expense Rent by Landlord shall not
      entitle Tenant to terminate this Lease.

      4.3 Definitions. As used in this Article 4, the following terms shall have
the meanings hereinafter set forth:

            (a) "Base Year" shall mean the calendar year set forth in Section
      9.1 of the Summary.


                                      -9-
<PAGE>

            (b) "Calendar Year" shall mean each calendar year in which any
      portion of the Lease Term falls, through and including the calendar year
      in which the Lease Term expires.

      4.4 Operating Expenses. The term "Operating Expenses" shall consist of all
operating expenses of the Project, including without limitation those specified
below, which shall be computed on a cash basis and shall consist of all
expenditures by Landlord to maintain in quality, first-class condition all
facilities in operation from the beginning of the Term of this Lease and such
additional facilities in subsequent years as may be determined by Landlord to be
necessary or generally beneficial to the Project. The term Operating Expenses as
used herein shall mean all expenses, costs and disbursements of every kind and
nature which Landlord shall pay or become obligated to pay because of or in
connection with the ownership (excluding the costs described in Items 1 through
___ below in this Section 4.4), management, operation, maintenance and repair of
the Project, including without limitation the following:

            (a) Wages, salaries, taxes, insurance and related expenses and
      benefits of all on-site and off-site employees directly engaged in the
      operation, maintenance or access control of the Project.

            (b) All supplies, tools, equipment and materials used in the
      operation and maintenance of the Project, including any lease payments
      therefor.

            (c) Cost of all utilities for the Project (including, without
      limitation, the Project Common Areas), including the cost of water, power
      (other than Clean Room Electrical Costs (as defined in Section 5.6 of this
      Lease)), sewer, heating, lighting, air conditioning and ventilation.

            (d) Cost of all maintenance, repairs and replacements, janitorial,
      building engineering, landscaping, security, legal, other consulting fees
      and service agreements for the Project and the equipment therein,
      including without limitation alarm service, window cleaning and elevator
      maintenance.

            (e) Cost of all insurance carried by Landlord in connection with the
      Project and Landlord's personal property used in connection therewith.

            (f) All real property taxes and assessments levied against the
      Project and the various estates therein, all personal property taxes
      levied on personal property of Landlord used in the management, operation,
      maintenance and repair of the Project, all taxes, assessments and
      reassessments of every kind and nature whatsoever levied or assessed in
      lieu of or in substitution for existing or additional real or personal
      property taxes and assessments on the Project, service payment in lieu of
      taxes, excises, transit charges and fees, housing, park and child care
      assessments, development and other assessments, reassessments, levies,
      fees or charges, general and special, ordinary and extraordinary,
      unforeseen as well as foreseen, of any kind which are assessed, levied,
      charged, confirmed, or imposed by any public authority upon the Project,
      its operations or the rent received from the Project, or amounts necessary
      to be expended because of governmental orders, whether general or special,
      ordinary or extraordinary, unforeseen as well as foreseen, of any kind and
      nature for public improvements, services, benefits, or any other purposes
      which are assessed, levied, confirmed, imposed or become a lien upon the
      Premises or Project or become payable during the Lease Term (hereinafter
      collectively "Impositions"). In the case of any Impositions which may be
      evidenced by improvement or other bonds or which may be paid in annual or
      other periodic installments, Landlord shall elect to cause such bonds to
      be issued or cause such assessment to be paid in installments over the
      maximum period permitted by law. Nothing contained in this Lease shall
      require Tenant to pay any franchise, estate, inheritance or succession
      transfer tax of Landlord, or any income, profits or revenue tax or charge,
      upon the net income of Landlord from all sources; provided, however, that
      if at any time during the Lease Term under the laws of the United States
      government or the State of California, or any political subdivision
      thereof, a tax or excise on Rent is levied or assessed by any such
      political body against Landlord on account of collection of Rent, or a
      portion thereof, Tenant shall pay one hundred percent (100%) of any such
      tax or excise as Additional Rent.

            (g) Repairs, replacements and general maintenance (excluding repairs
      and general maintenance paid by proceeds of insurance or by Tenant or
      other third parties, and alterations attributable solely to tenants of the
      Building other than Tenant).


                                      -10-
<PAGE>

            (h) All maintenance costs relating to public and service areas of
      the Project, including without limitation, sidewalks, landscaping, service
      areas, mechanical rooms and Project exteriors.

            (i) A management cost recovery equal to three percent (3%) of
      Project Rent collections.

            (j) Amounts payable under the Declaration with respect to
      performance of work or provision of goods or services the cost of which is
      otherwise includable as Operating Expenses.

      As provided in Section 4.1(b), certain costs are incurred generally with
respect to the entire Project, such as the real property taxes and assessments
described in Section 4.4(f) and the costs of maintaining and repairing the
Project Common Areas (i.e., the areas outside of the exterior of each of the
Buildings in the Project) are allocated among the various Buildings in
proportion to the prospective rentable areas of each of the Buildings in the
Project. For example, if the Building constitutes twenty-five percent (25%) of
the rentable area in the Project, then twenty-five percent (25%) of the
Operating Expenses incurred generally for the Project would be allocated to the
Building. Costs incurred with respect to a particular Building are treated as
Operating Expenses for the Building only. Repairs, maintenance and utilities
with respect to one Building are treated as Operating Expenses for only that
Building.

      Notwithstanding anything to the contrary contained in this Lease,
"Operating Expenses" shall not include any of the following: (1) any ground
lease rental; (2) capital expenditures to the extent the same constitute
upgrades as opposed to repairs or replacements, unless required to comply with
applicable requirements of municipal, county, state, federal and other
applicable governmental authorities; (3) costs incurred for repair of damage to
the Project to the extent reimbursed by insurance proceeds, provided that
insurance deductibles shall be included in Operating Expenses; (4) costs,
including permit, license and inspection costs, incurred with respect to the
installation of tenant improvements to other tenant's leased premises within the
Project or incurred in renovating or otherwise improving, decorating, painting
or redecorating vacant leasable space within the Project; (5) depreciation,
amortization and interest payments, except on materials, tools, supplies and
vendor-type equipment purchased by Landlord to enable Landlord to supply
services Landlord might otherwise contract for with a third party where such
depreciation, amortization and interest payments would otherwise have been
included in the charge for such third party's services; (6) marketing costs,
including leasing commissions, attorneys' fees in connection with the
negotiation and preparation of letters, deal memos, letters of intent, leases,
subleases and/or assignments, space planning costs, and other costs and expenses
incurred in connection with lease, sublease and/or assignment negotiations and
transactions with present or prospective tenants or other occupants of the
Project; (7) expenses in connection with services which are not available to
Tenant; (8) legal fees and related expenses and legal costs incurred by Landlord
(together with any damages awarded against Landlord) due to the violation by
Landlord or any tenant of the terms and conditions of any lease of space in the
Project; (9) overhead and profit paid to Landlord or to subsidiaries or
affiliates of Landlord for goods and/or services in the Project to the extent
the same exceeds the costs of such goods and/or services rendered by qualified,
unaffiliated third parties on a competitive basis; (10) interest, principal,
points and fees on debts or amortization on any mortgage or mortgages or any
other debt instrument encumbering the Project; (11) Landlord's general corporate
overhead and general and administrative expenses not specifically incurred in
the management, maintenance and operation of the Project; (12) costs incurred in
correcting any non-compliance of the Project with applicable requirements of
municipal, county, state, federal and other applicable governmental authorities
where such non-compliance was existing as of the delivery of possession of the
Premises to Tenant; (13) costs arising from the presence of any existing
Hazardous Substances upon or beneath the Project; (14) increased costs of
performance arising from Landlord's gross negligence or willful misconduct; (15)
costs arising from Landlord's charitable or political contributions; and (16)
costs (other than ordinary maintenance) for sculpture, paintings and other
objects of art; (17) Clean Room Electrical Costs; (18) costs associated with the
operation of the business of the ownership of the Building for an entity that
constitutes Landlord, as distinguished from the cost of Building operations,
including without limitation the cost of partnership or corporate accounting and
legal matters; defending or prosecuting any lawsuit with any mortgagee, lender,
ground lessor, broker, tenant, occupant, or prospective tenant or occupant;
selling or syndicating any of Landlord's interest in the Building,; disputes
between Landlord and Landlord's property manager; and (19) wages, salaries and
other compensation paid to any executive employee of Landlord or Landlord's
property manager above the grade of Building Manager for the Building or paid to
any off-site personnel.


                                      -11-
<PAGE>

      Notwithstanding any other provision herein to the contrary, it is agreed
that in the event the Building is not at least ninety-five percent (95%)
occupied during any calendar year of the Lease Term, an adjustment shall be made
in computing the Operating Expenses for such year so that the Operating Expenses
shall be computed for such year as though the Building had been ninety-five
percent (95%) occupied during such year. Landlord and Tenant agree that Expense
Rent shall be paid during the entire term of this Lease, beginning with the
Lease Commencement Date and continuing through the Lease Expiration Date. In the
event that (a) assessments for any community facilities district are included in
Operating Expenses for the Base Year and (b) in any calendar year after the Base
Year such community facilities district assessments are not payable, then for
purposes of determining Operating Expenses for the Base Year the amount of the
community facilities district assessment for that Base Year shall be excluded
from Operating Expenses. Landlord may elect to segregate Operating Expenses into
two or more subcategories. For example, Landlord may segregate electrical costs
and/or other utility costs from other Operating Expenses. If Landlord elects to
make that segregation, (a) Expense Rent shall be determined separately for each
such subcategory by making separate calculations of the increase in the cost of
each subcategory of Operating Expense from the Base Year to the applicable
calendar year, and (b) Tenant shall pay as Expense Rent Tenant's Percentage
Share of the Building's Share of the increase in each such subcategory.
Notwithstanding anything in the Lease to the contrary, for purposes of
determining Operating Expenses for any calendar year subsequent to the Base
Year, electrical costs shall be deemed to be the greater of electrical costs
incurred in the Base Year and electrical costs for the applicable calendar year.

      4.5 Monthly Rent Payments. Rent under Sections 4.1(a) and (b) shall be due
and payable in twelve (12) equal installments of one-twelfth (1/12) each on the
first day of each calendar month during the Lease Term and any extensions or
renewals thereof without demand, counterclaim or offset. If the Lease Term
commences on a day other than the first day of a calendar month or ends on a day
other than the last day of a calendar month, then the Rent under Sections 4.1(a)
and (b) for the first and last fractional months shall be appropriately
prorated. If the Lease Term commences on a day other than the first day of a
calendar year, for purposes of calculating Expense Rent, the Operating Expenses
for such year and for the Base Year shall each be reduced by the proportion that
the number of days of the Lease Term falling within such calendar year bears to
three hundred sixty-five (365) days. Rent under Section 4.1(c) and any other
amounts due under this Lease shall be collected pursuant to written notices from
Landlord and payment shall be due within fifteen (15) days of such notice.

      4.6 Additional Rent. Tenant shall also pay as additional rent all such
other sums of money including without limitation Clean Room Electrical Costs
payable pursuant to Section 5.6 of this Lease, as shall become due and payable
by Tenant to Landlord ("Additional Rent"). Such Additional Rent, including
without limitation, all amounts Tenant shall be responsible for paying pursuant
to the terms of Section 7.3 of this Lease, shall not be subject to abatement,
set-off or deduction whatsoever. Except for amounts billed to Tenant under the
terms of the Work Letter (which shall be payable pursuant to the terms of the
Work Letter), Tenant shall pay to Landlord all amounts of Additional Rent within
fifteen (15) days of Tenant's receipt of a bill therefor.

      4.7 No Deduction or Offset. Rent shall be paid to Landlord, without
abatement, deduction or offset, in lawful money of the United States of America
at Landlord's address as set forth in the Summary or to such other person or at
such place as Landlord may from time to time designate in writing. No payment by
Tenant or receipt by Landlord of a lesser amount of Rent shall be other than on
account of the earliest rent or payment due, nor shall any endorsement or
statement on any check or letter accompanying any such check or payment
constitute an accord and satisfaction and Landlord may accept any such check or
payment or pursue any other remedy under this Lease, at law or in equity.

      4.8 Late Payment and Interest. Tenant acknowledges that the late payment
by Tenant to Landlord of any sums due under this Lease will cause Landlord to
incur costs not contemplated by this Lease, the exact amount of such costs being
extremely difficult and impracticable to fix. Such costs include, without
limitation, processing and accounting charges, and late charges that may be
imposed on Landlord by the terms of any encumbrance or note secured by all or
any portion of the Project. Accordingly, if any installment of Rent is not paid
within ten (10) days of the date when due, all such past due installments of
Rent shall bear interest from the due date until paid at a rate (the "Interest
Rate") equal to the lesser of (a) three per cent (3%) per annum over the prime
rate of interest announced from time to time by Wells Fargo Bank, National
Association, San Francisco, California or (b) the maximum lawful rate. In
addition, if any installment of Rent is not paid within ten (10) days of the
date when due, Tenant shall pay to Landlord a late charge equal to five percent
(5%) of the overdue amount. This provision shall


                                      -12-
<PAGE>

not relieve Tenant from payment of Rent at the time and in the manner herein
specified. The payment by Tenant and receipt by Landlord of late payment charges
and interest is not a release or waiver by Landlord of a default by Tenant or
prevent Landlord from exercising any of the other rights and remedies available
to Landlord under this Lease, at law or in equity.

      4.9 Security Deposit. Upon execution of this Lease, Tenant shall deposit
the amount specified in the Summary as a security deposit ("Security Deposit"),
with Landlord. The Security Deposit shall secure Tenant's obligations under this
Lease to pay Rent and other monetary amounts, to maintain the Premises and
repair damages thereto, to surrender the Premises to Landlord in clean condition
and repair upon termination of this Lease and to discharge Tenant's other
obligations hereunder. If Tenant fails to perform Tenant's obligations
hereunder, Landlord may, but without any obligation to do so, apply all or any
portion of the Security Deposit towards fulfillment of Tenant's unperformed
obligations. If Landlord does so apply any portion of the Security Deposit,
Tenant, upon demand by Landlord, shall immediately pay Landlord a sufficient
amount in cash to restore the Security Deposit to the original amount. Tenant's
failure to forthwith remit to Landlord an amount in cash sufficient to restore
the Security Deposit to the original sum deposited within five (5) days after
receipt of such demand shall constitute an "Event of Default" (defined in
Section 17). Landlord is hereby granted a security interest in the Security
Deposit in accordance with applicable provisions of the California Commercial
Code. The Security Deposit shall be held by Landlord without liability for
interest on the same. Landlord is entitled to commingle the security deposits
with its own funds and Landlord is not to be deemed a trustee or fiduciary for
Tenant in respect of the security deposit. Upon termination of this Lease, if
Tenant has then performed all of Tenant's obligations hereunder, Landlord shall
return the Security Deposit to Tenant. If Landlord sells or otherwise transfers
Landlord's right or interest under this Lease, Landlord may deliver the Security
Deposit to the transferee, whereupon Landlord shall be released from any further
liability to Tenant with respect to the Security Deposit.

                                    ARTICLE 5
                             SERVICES AND UTILITIES

      5.1 Basic Services. Landlord shall cause the following Basic Services to
be provided on all days during the Lease Term, unless otherwise stated below.

            (a) Subject to all governmental rules, regulations and guidelines
      applicable thereto, Landlord shall provide heating and air conditioning
      for normal comfort for normal office use in the Premises during "Building
      Hours", which for purposes of this Lease shall mean from Monday through
      Friday, during the period from 7:00 a.m. to 6:00 p.m., except for the date
      of observation of New Year's Day, Presidents' Day, Memorial Day,
      Independence Day, Labor Day, Thanksgiving Day, Christmas Day and other
      nationally recognized holidays (collectively the "Holidays").

            (b) Landlord shall provide adequate electrical wiring and facilities
      and power for normal general office use as determined by Landlord.
      Landlord shall replace, as part of Operating Expenses, lamps, starters and
      ballasts for Building standard lighting fixtures within the Premises.

            (c) Landlord shall provide access to city water from the regular
      Building outlets for drinking, lavatory and plumbing requirements within
      the Premises.

            (d) Landlord shall provide janitorial services five (5) days per
      week, except the date of observation of the Holidays, in and about the
      Premises and window washing services in a manner consistent with such
      services provided by owners of Comparable Buildings.

            (e) Landlord shall provide nonexclusive automatic passenger elevator
      service at all times.

            (f) Landlord shall provide nonexclusive freight elevator service
      subject to scheduling by Landlord.


                                      -13-
<PAGE>

            (g) Subject to Tenant's repair obligations set forth in Section 6
      below and the provisions of Section 4, Landlord shall operate and maintain
      the Building (including the structural components of the Building and the
      Building's systems and equipment) in a first-class manner and condition.

            (h) Landlord shall cause to be maintained such security and
      supervision program for the Project as Landlord determines to be
      appropriate in the exercise of its business judgment, which may include,
      without limitation, security personnel, cameras, roving patrols, a
      keyboard system and/or any other security measures which Landlord deems
      appropriate.

      5.2 Over Standard Use. If Tenant uses water in excess of that supplied by
Landlord pursuant to Section 5.1, or if Tenant's consumption of electricity
shall exceed five (5) watts per square foot of Rentable Area in the Premises,
calculated on an annualized basis for the hours described in Section 5.1(a)
above, or if Tenant shall consume electricity in the Premises at times other
than Building Hours at levels in excess of that which is customary for
first-class general office use, then Tenant shall pay to Landlord, upon billing,
the cost of such excess consumption, the cost of the installation, operation,
and maintenance of equipment which is installed in order to supply such excess
consumption, and the cost of the increased wear and tear on existing equipment
caused by such excess consumption. Landlord may from time to time install
devices to separately meter any utility use at Landlord's cost; provided that
meters for the Clean Room shall be installed and paid for as provided in Section
5.6. If Tenant desires to use heat, ventilation or air conditioning ("HVAC")
during hours other than those specified in Section 5.1 of this Lease, Tenant
shall give Landlord such prior notice as Landlord shall from time to time
establish as appropriate, of Tenant's desired use and Landlord shall supply such
after-hours HVAC to Tenant subject to Tenant's payment to Landlord of $50.00 per
hour for such excess usage of HVAC after application of any available HVAC
Overtime Credits, as defined and provided below. "HVAC Overtime Credits" means a
credit for thirty (30) hours of excess HVAC usage per calendar month commencing
on the Commencement Date. If in any calendar month Tenant does not apply all of
the thirty (30) hours of HVAC Overtime Credits initially attributable to that
calendar month, the unapplied balance may be carried over to successive calendar
months until applied; provided that at no time shall the aggregate number of
HVAC Overtime Credits being carried over exceed 360 hours and no HVAC Overtime
Credits initially attributable to a calendar month may be carried over for more
than 12 calendar months after that month. HVAC Overtime Credits initially
attributable to a calendar month shall be the first applied to excess HVAC usage
in that calendar month and then the oldest carryover HVAC Overtime Credits (if
any) shall be applied to excess HVAC usage.

      5.3 Interruption of Use. Tenant agrees that Landlord shall not be liable
for damages, by abatement of Rent or otherwise, for failure to furnish or delay
in furnishing any service (including telephone and telecommunication services),
or for any diminution or change in the quality or quantity thereof, when such
failure or delay or diminution or change is occasioned, in whole or in part, by
repairs, replacements, or improvements, by any strike, lockout or other labor
trouble, by inability to secure electricity, gas, water or other fuel at the
Project after reasonable effort to do so, by electricity blackout or brownout,
by any accident or casualty whatsoever, by act or default of Tenant or other
tenants, or by any other cause beyond Landlord's reasonable control, and such
failures or delays or diminution shall never be deemed to constitute an eviction
or disturbance of Tenant's use and possession of the Premises or relieve Tenant
from paying Rent or performing any of its obligations under this Lease.
Furthermore, Landlord shall not be liable under any circumstances for a loss of,
or injury to, property or for injury to, or interference with, Tenant's
business, including, without limitation, loss of profits, however occurring,
through or in connection with or incidental to a failure to furnish any of the
services or utilities.

      5.4 Additional Services. Landlord shall also have the exclusive right, but
not the obligation, to provide any additional services which may be requested by
Tenant, including, without limitation, locksmithing, lamp replacement for
non-Building standard lamps or fixtures, additional janitorial service, and
additional repairs and maintenance, provided that Tenant shall pay to Landlord
upon billing, the actual cost to Landlord of providing such additional services,
plus a reasonable administration fee, and same shall be deemed Additional Rent
hereunder and shall be billed on a monthly basis.

      5.5 Keys and Locks. Landlord shall furnish Tenant twenty-five (25) keys
for each corridor door entering the Premises. Additional keys shall be furnished
at a charge by Landlord on an order signed by Tenant. All such keys shall remain
the property of Landlord. No additional locks shall be allowed on any door of
the Premises without Landlord's prior written permission, and Tenant shall not
make or permit to be made any duplicate keys,


                                      -14-
<PAGE>

except those furnished by Landlord. Upon termination of this Lease, Tenant shall
surrender to Landlord all keys of the Premises, and give to Landlord the
combination of all locks for safes, safe cabinets and vault doors, if any, in
the Premises.

      5.6 Clean Room Electrical Costs. In addition to the Base Rent and Expense
Rent, Tenant shall pay to Landlord, as Additional Rent, the amount by which
Clean Room Electrical Costs (as defined below) in any calendar month exceed the
Clean Room Electrical Costs Base Amount. As used herein, (a) the term "Clean
Room Electrical Costs" means the cost of electrical service to the clean room
area (the "Clean Room") of the Premises as shown on the plans approved by
Landlord pursuant to Exhibit "C" and (b) "Clean Room Electrical Cost Base
Amount" means the product of (i) $0.25, multiplied by (ii) the Rentable Area of
the Clean Room as determined by Landlord. Landlord shall install devices to
separately meter all electricity furnished to the Clean Room and Tenant shall
pay to Landlord, in accordance with Section 4.6 of this Lease, the cost of the
installation, operation and maintenance of such metering devices; provided that
the cost of installation of those meters shall be paid out of the Allowance as
provided in Exhibit "C."

      5.7 Rent Abatement. Notwithstanding anything to the contrary in Section
5.3 or elsewhere in this Lease, if (a) Landlord fails to provide Tenant with the
electrical service or elevator service described in Section 5.1, or Landlord's
enters the Premises and such entry interferes with Tenant's reasonable use of
the Premises (b) such failure or Landlord's entry is not due to any one or more
force majeure events or to an event covered by Article 10, (c) Tenant has given
Landlord reasonably prompt written or oral notice of such failure or that such
entry by Landlord is unreasonably interfering with Tenant's use of the Premises
(provided that such notice shall not be required in the event Landlord has
actual knowledge that the failure to provide electrical services or elevator
service or Landlord's entry is unreasonably interfering with Tenant's use of the
Premises) and (d) as a result of such failure all or any part of the Premises
are rendered untenantable (and, as a result, all or such part of the Premises
are not used by Tenant during the applicable period) for more than five (5)
consecutive business days, then Tenant shall be entitled to an abatement of Rent
proportional to the extent to which the Premises are thereby rendered unusable
by Tenant, commencing with the later of (i) the sixth business day during which
such untenantability continues or (ii) the sixth business day after Landlord
receives such notice from Tenant, until the Premises (or part thereof affected)
are again usable or until Tenant again uses the Premises (or part thereof
rendered unusable) in its business, whichever first occurs. The foregoing rental
abatement shall be Tenant's exclusive remedy therefor. Notwithstanding the
foregoing, the provisions of Article 10 below and not the provisions of this
subsection shall govern in the event of casualty damage to the Premises or
Building and the provisions of Article 12 below and not the provisions of this
subsection shall govern in the event of condemnation of all or a part of the
Premises or Building.

                                   ARTICLE 6
                                    REPAIRS

      6.1 Tenant's Repairs. From and after delivery of possession of the
Premises to Tenant, Tenant shall keep, maintain and preserve the Premises in a
first class condition and repair, and shall, as and when needed, at Tenant's
sole cost and expense, make all repairs to the Premises and every part thereof
(other than elements of the Premises to be maintained and repaired by Landlord
pursuant to this Lease) and all personal property, trade fixtures and equipment
within the Premises.

      6.2 Landlord's Repairs. Landlord shall cause to be kept, maintained and
preserved in first-class condition and repair, the roof, structure and
foundation, integrated Building utility and mechanical systems, parking
facilities and other Project Common Areas, the costs of which shall be included
in Operating Expenses; provided, however, that to the extent such maintenance
and/or repair work is (i) attributable to items installed in the Premises which
are above standard interior improvements (such as, for example, custom lighting,
special HVAC and/or electrical panels or systems, kitchen or restroom facilities
and appliances constructed or instated within the Premises), (ii) attributable
to the installation, as a part of the Tenant Improvements, Tenant's Alterations
or Tenant's trade fixtures, of items which are less than first-class in quality,
workmanship or manner of installation, and/or (iii) necessitated by the
negligence or willful misconduct of Tenant and/or any of Tenant's subtenants
and/or assignees and/or their respective agents, employees, representatives,
licensees, contractors and/or invitees, then Tenant shall pay to Landlord the
cost of such maintenance and/or repairs. Landlord shall not be liable for any
failure to make any such repairs or to perform any maintenance unless such
failure shall persist for an unreasonable


                                      -15-
<PAGE>

time after written notice of the need for such repairs or maintenance is given
to Landlord by Tenant. Subject to the provisions of Articles 10 and 12 below,
there shall be no abatement of Rent and no liability of Landlord by reason of
any injury to or interference with Tenant's business arising from the making of
any repairs, alterations or improvements in or to any portion of the Project or
the Premises or in or to fixtures, appurtenances and equipment therein. Tenant
waives any right which Tenant may have to make repairs at Landlord's expense
under any law, statute or ordinance now or hereafter in effect (including,
without limitation, Sections 1941 and 1942 of the California Civil Code).

      6.3 Entry. Landlord and its employees, agents, representatives,
consultants and/or contractors shall have the right from time to time without
notice to Tenant (although Landlord shall use reasonable efforts to provide
Tenant with such prior notice as is reasonably practicable under the
circumstances, which, notwithstanding anything to the contrary in this Lease as
to the manner of giving of notices, may be oral or written notice, and provided
that no such prior notice shall be required in the event of an emergency or for
scheduled provision of services to the Premises) to enter the Premises to
inspect the same, to supply any service to be provided by Landlord to Tenant
hereunder, to show the Premises to prospective purchasers, encumbrancers or
tenants, to post notices of non-responsibility, to alter, improve or repair the
Premises or any other portion of the Building, all without being deemed guilty
of any eviction of Tenant and without abatement of Rent, and may, in order to
carry out such purposes, erect scaffolding and other necessary structures where
required by the character of the work to be performed. Landlord shall use
reasonable efforts to minimize unreasonable interference with the operation of
Tenant's business from the Premises resulting from any such entry (except in the
event of an emergency). Tenant hereby waives any claim for damages for any
injury or inconvenience to or interference with Tenant's business, any loss of
occupancy or quiet enjoyment of the Premises, and any other loss in, upon and
about the Premises or the Project. Landlord shall at all times have and retain a
key with which to unlock all doors to and in the Premises. In the event of an
emergency, Landlord shall have the right to use any and all means which Landlord
may deem proper to open said doors in order to obtain entry to the Premises. Any
entry to the Premises obtained by Landlord by any of said means, or otherwise,
shall not be construed or deemed to be a forcible or unlawful entry into the
Premises, or an eviction of Tenant from the Premises or any portion thereof. It
is understood and agreed that no provision of this Lease shall be construed as
obligating Landlord to perform any repairs, alterations or decorations, except
as otherwise expressly agreed herein by Landlord.

                                    ARTICLE 7
                                   ALTERATIONS

      7.1 Landlord's Consent to Alterations. Tenant may not make any
improvements, alterations, additions or changes to the Premises (collectively,
the "Alterations") without first procuring the prior written consent of Landlord
to such Alterations, which consent shall be requested by Tenant not less than
thirty (30) days prior to the commencement thereof, and which consent shall not
be unreasonably withheld by Landlord. The construction of the initial
improvements to the Premises shall be completed by Landlord and shall be
governed by the terms of the Work Letter.

      7.2 Manner of Construction. Landlord may impose, as a condition of its
consent to all Alterations or repairs of the Premises or about the Premises,
such requirements as Landlord in its sole discretion may deem desirable,
including, but not limited to, the requirement that upon Landlord's request,
Tenant shall, at Tenant's expense, remove such Alterations upon the expiration
or any early termination of the Lease Term, and/or the requirement that Tenant
utilize for such purposes only contractors, materials, mechanics and management
selected by Tenant and approved by Landlord (which approval shall not be
unreasonably withheld); provided, however, that Tenant shall utilize
subcontractors of Landlord's selection to perform all work that may affect the
Project systems and equipment, structural aspects of the Project, the "Base,
Shell and Core" (as defined in the Work Letter), or exterior appearance of the
Project or Project Common Areas. Tenant shall construct such Alterations and
perform such repairs in conformance with any and all applicable rules and
regulations of any federal, state, county or municipal code or ordinance and
pursuant to a valid building permit, issued by the City of Novato and in
conformance with Landlord's construction rules and regulations. Any Alterations
shall be performed in conformance with plans, specifications and working
drawings first approved by Landlord. Landlord's approval of the plans,
specifications and working drawings for Tenant's Alterations shall create no
responsibility or liability on the part of Landlord for their completeness,
design sufficiency, or compliance with all laws, rules and regulations of
governmental agencies or authorities. All work with respect to any Alterations
must be done in a good and


                                      -16-
<PAGE>

workmanlike manner and diligently prosecuted to completion to the end that the
Premises shall at all times be a complete unit except during the period of work.
In performing the work of any such Alterations, Tenant shall have the work
performed in such manner as not to obstruct access to the Project for any other
lessee of the Project, and as not to obstruct the business of Landlord or other
lessees in the Project, or interfere with the labor force working in the
Project. In the event that Tenant makes any Alterations, Tenant agrees to carry
"Builder's All Risk" insurance in an amount approved by Landlord covering the
construction of such Alterations, and such other insurance as Landlord may
require, it being understood and agreed that all of such Alterations shall be
insured by Tenant pursuant to Article 9 immediately upon completion thereof. In
addition, Landlord may, in its discretion, require Tenant to obtain a lien and
completion bond or some alternate form of security satisfactory to Landlord in
an amount sufficient to ensure the lien-free completion of such Alterations and
naming Landlord as a co-obligee. Upon completion of any Alterations, Tenant
agrees to cause a Notice of Completion to be recorded in the Office of the
Recorder of the County of Marin in accordance with Section 3093 of the Civil
Code of the State of California or any successor statute and Tenant shall
deliver to the Building management office a reproducible copy of the "as built"
drawings of the Alterations.

      7.3 Payment for Improvements. The cost of all Alterations shall be paid by
Tenant. In the event Tenant orders any Alteration or repair directly from
Landlord, or from the contractor selected by Landlord, the charges for such work
shall be deemed Additional Rent under this Lease, payable upon billing therefor,
either periodically during construction or upon the substantial completion of
such work, at Landlord's option. Upon completion of such work, Tenant shall
deliver to Landlord, if payment is made directly to contractors, evidence of
payment, contractors' affidavits and full and final waivers of all liens for
labor, services or materials. If Tenant orders any work directly from Landlord,
Tenant shall pay to Landlord the cost thereof, together with an additional three
percent (3%) of the cost of such work to cover overhead, general conditions,
fees and other costs and expenses arising from Landlord's involvement with such
work. If Tenant does not order any work directly from Landlord, Tenant shall
reimburse Landlord for Landlord's reasonable out-of-pocket costs and expenses
actually incurred in connection with Landlord's review of and/or involvement
with such work.

      7.4 Landlord's Property and Fixtures. All Alterations, improvements,
fixtures and/or equipment which may be installed or placed in or about the
Premises, and all signs installed in, on or about the Premises, from time to
time, shall be at the sole cost of Tenant and shall be and become the property
of Landlord, except that Tenant may remove any Alterations, improvements,
fixtures and/or equipment which Tenant can substantiate to Landlord have not
been paid for with any Tenant improvement allowance funds provided to Tenant by
Landlord, provided Tenant repairs any damage to the Premises and Project caused
by such removal. Furthermore, if Landlord, as a condition to Landlord's consent
to any Alterations, requires that Tenant remove any Alterations upon the
expiration or earlier termination of the Lease Term upon Landlord's request,
Landlord may, by written notice to Tenant given prior to or within thirty (30)
days following the end of the Lease Term or any earlier termination of this
Lease, require Tenant at Tenant's expense to remove such Alterations and to
repair any damage to the Premises and Project caused by such removal. If Tenant
fails to promptly complete such removal and/or to repair any damage caused by
the removal of any Alterations, Landlord may do so and may charge the cost
thereof to Tenant. Tenant hereby indemnifies and holds Landlord harmless from
any liability, cost, obligation, expense or claim of lien in any manner relating
to the installation, placement, removal or financing of any such Alterations,
improvements, fixtures and/or equipment in, on or about the Premises.

                                    ARTICLE 8
                             COVENANT AGAINST LIENS

      Tenant has no authority or power to cause or permit any lien or
encumbrance of any kind whatsoever, whether created by act of Tenant, operation
of law or otherwise, to attach to or be placed upon the Project or Premises or
any part thereof, and any and all liens and encumbrances created by Tenant shall
attach to Tenant's interest only. Landlord shall have the right at all times to
post and keep posted on the Premises any notice which it deems necessary for
protection from such liens. Tenant covenants and agrees not to suffer or permit
any lien of mechanics or materialmen or others to be placed against the Project
or the Premises or any part thereof with respect to work or services claimed to
have been performed for or materials claimed to have been furnished to Tenant or
the Premises, and in case of any such lien attaching or notice of any lien,
Tenant covenants and agrees to cause it to be immediately released and removed
of record. Notwithstanding anything to the contrary set forth in this Lease, in
the event that such lien is not released and removed on or before the date
notice of such lien is delivered by Landlord to


                                      -17-
<PAGE>

Tenant, Landlord, at its sole option, may immediately take all action necessary
to release and remove such lien, without any duty to investigate the validity
thereof, and all sums, costs and expenses, including attorneys' fees and actual
costs, incurred by Landlord in connection with such lien shall be deemed
Additional Rent under this Lease and shall immediately be due and payable by
Tenant.

                                    ARTICLE 9
                                    INSURANCE

      9.1 Landlord Coverage: All Risk. During the Term, Landlord shall procure
and maintain in full force and effect with respect to the Project, a policy or
policies of all risk property insurance (including sprinkler, vandalism and
malicious mischief coverage, earthquake and flood coverage at Landlord's option,
and any other endorsements required by any ground lessor or the holder of any
mortgage) in an amount customarily carried by owners of Comparable Buildings. If
because of the nature of Tenant's operations the annual premiums charged
Landlord for such insurance exceed the standard premium rates or result in
increased exposure, then Tenant, within fifteen (15) days of receipt of
appropriate premium invoices, shall reimburse Landlord for such increased
amount. Additionally Landlord may maintain such additional insurance, including,
without limitation, liability insurance and/or rent insurance, as Landlord may
in its sole discretion elect. The cost of all such additional insurance shall
also be part of the Operating Expenses. Landlord shall not be obligated to
insure, and shall not assume any liability of risk of loss for, any of Tenant's
furniture, equipment, machinery, goods, supplies, improvements or alterations
upon the Premises. Any or all of Landlord's insurance may be provided by blanket
coverage maintained by Landlord or any affiliate of Landlord's under its
insurance program for its portfolio of properties or by Landlord or any
affiliate of Landlord's program of self insurance, and in such event Operating
Expenses shall include the portion of the reasonable cost of blanket insurance
or self-insurance that is allocated to the Project. Increases in insurance costs
resulting from unique aspects of the Project or Tenants in the Project (as
opposed to general increases in insurance costs applicable to the insurance
market in general) shall not be included in Operating Expenses for purposes of
this Lease.

      9.2 Tenant Coverage.

            (a) All Risk Insurance. During the Lease Term and at its own cost
      and expense, Tenant shall maintain in full force and effect a policy or
      policies of all risk property insurance (including sprinkler, vandalism
      and malicious mischief coverage and including earthquake and flood
      coverage at Tenant's option) in an amount adequate to cover damage to the
      Premises, including without limitation Tenant's Improvements as defined in
      the Work Letter, merchandise, fixtures, trade fixtures, furniture,
      furnishings, equipment, goods, inventory and other personal property
      located on the Premises or in the Project, insuring the full replacement
      value of such items.

            (b) General Liability. During the Lease Term and at its own cost and
      expense, Tenant shall maintain in full force and effect a policy or
      policies of commercial general liability insurance insuring Tenant's
      activities with respect to the Premises, Building and/or Project against
      loss, damage or liability for personal injury or death of any person or
      loss or damage to property occurring in, upon or about the Premises,
      Building and/or Project with the following minimum limits: General
      Aggregate $2,000,000.00; Products/Completed Operations Aggregate
      $2,000,000.00; Each Occurrence $1,000,000.00; Personal and Advertising
      Injury $1,000,000.00; Medical Payments $5,000.00 per person; such
      commercial general liability insurance shall include broad form
      contractual liability insurance coverage which shall insure Tenant's
      performance of the indemnity provisions in this Lease.

            (c) Workers' Compensation. During the Lease Term and at its own cost
      and expense, Tenant shall maintain in full force and effect the statutory
      amount of workers' compensation insurance required by the State of
      California for the benefit of Tenant's employees, and employer's liability
      insurance with the following limits: Bodily injury by disease per person
      $1,000,000.00; Bodily injury by accident policy limit $1,000,000.00;
      Bodily injury by disease policy limit $1,000,000.00.

      Tenant agrees that if Tenant does not procure and maintain such insurance
continuously, Landlord may (but shall not be required to) procure such insurance
on Tenant's behalf and Tenant shall pay to Landlord the cost thereof, as
Additional Rent, within fifteen (15) days of Tenant's receipt of a bill
therefor.


                                      -18-
<PAGE>

      9.3 General Insurance Requirements.

            (a) Requirements. All insurance required under this Article 9 to be
      obtained by Tenant shall be issued by such good and reputable insurance
      companies qualified to do and doing business in California and having a
      rating of not less than "A-X" as rated in the most current copy of Best's
      Insurance report in the form customary to the locality. All such Tenant
      insurance shall include (i) an endorsement expressly providing that such
      policies shall not be cancelable or subject to reduction of coverage or
      otherwise be subject to modification except after thirty (30) days' prior
      written notice to the parties named as insureds in this Article 9, (ii) an
      endorsement providing that Landlord, its successors, assigns, and nominees
      holding any interest in the Premises, including without limitation any
      ground lessor and the holder of any mortgage, shall be named as additional
      insureds under each such policy of insurance maintained by Tenant pursuant
      to this Lease, (iii) an endorsement providing that such insurance as is
      afforded under Tenant's policy is primary as respects Landlord and that
      any other insurance maintained by Landlord is excess and non-contributing
      with other insurance required under this Article 9, (iv) an endorsement
      deleting any employee exclusion on personal injury covered, (v) an
      endorsement including employees as additional insureds, (vi) an
      endorsement deleting any liquor liability exclusion and (vii) an
      endorsement providing for coverage of employer's automobile liability. All
      such insurance shall provide for severability of interests; shall provide
      that an act or omission of one of the named insureds shall not reduce or
      avoid coverage to the other named insured; and shall afford coverage for
      all claims based on acts, omissions injury and damage which claims
      occurred or arose (or the onset of which occurred or arose) in full or in
      part during the policy period. Expiration of Tenant's policy shall not
      limit recovery thereunder; "claims made" insurance policies are not
      acceptable to satisfy Tenant's insurance requirements under this Article
      9. Tenant shall furnish to Landlord, upon the Commencement Date and
      thereafter within thirty (30) days prior to the expiration of each such
      policy, a Certificate of Insurance and endorsement(s) affording evidence
      of the above insurance requirements issued by the insurance carrier of
      each policy of insurance carried by Tenant pursuant hereto.

            (b) Tenant's Use. Tenant will not keep, use, sell or offer for sale
      in, or upon the Premises any article which may be prohibited by any
      insurance policy periodically in force covering the Building or Project.
      If Tenant's occupancy or business in or on the Premises, unless Landlord
      has consented to the same, results in any increase in premiums for the
      insurance periodically carried by Landlord with respect to the Building or
      Project, Tenant shall pay any such increase in premiums as Additional Rent
      within ten (10) days after being billed therefor by Landlord. Landlord
      acknowledges that it has consented to the use of the Clean Room at the
      Premises and to the Permitted Hazardous Substances. In determining whether
      increased premiums are a result of Tenant's use of the Premises, a
      schedule issued by the organization computing the insurance rate on the
      Building or Project or the Tenant Improvements showing the various
      components of such rate, shall be conclusive evidence of the items which
      make up such rate.

            (c) Waiver of Subrogation. Any policy or policies of property
      insurance, which either party obtains in connection with the Premises, or
      Tenant's personal property therein, shall include a clause or endorsement
      denying the insurer any rights of subrogation against the other party to
      the extent rights have been waived by the insured prior to the occurrence
      of injury or loss. Landlord and Tenant hereby waive any rights of recovery
      against the other for injury or loss due to hazards covered by insurance
      containing such a waiver of subrogation clause or endorsements to the
      extent of the injury or loss covered thereby and agree to obtain such a
      waiver from their respective insurance carriers and upon request deliver a
      copy thereof to the other party; each party shall provide written notice
      to the other party if such waiver is not obtained and shall indemnify,
      defend and hold the other harmless from all liabilities, penalties,
      losses, costs, expenses, demands, causes of action, claims, judgments or
      damages arising from the indemnifying party's failure to obtain such a
      waiver from its insurance company unless such a waiver is not customarily
      available.

      9.4 Indemnification and Waiver. To the extent not prohibited by law,
Landlord, its partners, members, officers, directors, shareholders,
beneficiaries, agents, servants and employees (collectively, the "Landlord
Parties") shall not be liable for any damage either to person or property or
resulting from the loss of use thereof, which damage is sustained by Tenant or
by other persons claiming through Tenant. Tenant shall indemnify, defend,
protect and hold harmless Landlord Parties from any and all loss, cost, damage,
expense, liability and claims (including without limitation court costs and
reasonable attorneys' fees) (collectively "Claims") incurred in


                                      -19-
<PAGE>

connection with or arising from any cause in, on or about the Premises from and
after the earlier of (i) the date Tenant conducts any activities in the Premises
or the Project or (ii) the Lease Commencement Date, and continuing until the
later of (A) the expiration or termination of the Lease Term, or (B) the date
Tenant vacates and surrenders possession of the Premises to Landlord; provided
that the foregoing indemnity shall not apply to any Claims to the extent finally
determined by a court of competent jurisdiction to have been caused by
Landlord's sole gross negligence or willful misconduct. The provisions of this
Section 9.4 shall survive the expiration or sooner termination of this Lease
with respect to any claims or liability occurring prior to such expiration or
termination.

                                   ARTICLE 10
                             DAMAGE AND DESTRUCTION

      10.1 Repair of Damage to Premises by Landlord. Tenant shall promptly
notify Landlord of any damage to the Premises resulting from fire or any other
casualty. If the Premises or any common areas of the Project serving or
providing access to the Premises shall be damaged by fire or other casualty,
Landlord shall promptly and diligently prosecute to completion, subject to
reasonable delays for insurance adjustment or other matters beyond Landlord's
reasonable control, and subject to all other terms of this Article 10, restore
the Base, Shell and Core of the Premises and such common areas. Such restoration
shall be to substantially the same condition of the Base, Shell and Core of the
Premises and common areas prior to the casualty, except for modifications
required by zoning and building codes and other laws or by the holder of a
mortgage on the Project, or any other modifications to the common areas deemed
desirable by Landlord, provided access to the Premises and any common restrooms
serving the Premises shall not be materially impaired. Notwithstanding any other
provision of this Lease, upon the occurrence of any damage to the Premises,
Tenant shall assign to Landlord (or to any party designated by Landlord) all
insurance proceeds payable to Tenant under Tenant's insurance with respect to
Tenant Improvements required under Article 9 of this Lease, and Landlord shall
repair any injury or damage to the Tenant Improvements installed in the Premises
and shall return such Tenant Improvements to their original condition; provided
that if the cost of such repair by Landlord exceeds the amount of insurance
proceeds received by Landlord from Tenant's insurance, the cost of such repairs
shall be paid by Tenant to Landlord prior to Landlord's repair of the damage. In
connection with such repairs and replacements Tenant shall, prior to the
commencement of construction, submit to Landlord for Landlord's review and
approval all plans specifications and working drawings relating thereto. Such
submittal of plans and construction of improvements shall be performed in
substantial compliance with the terms of the Work Letter as though such
construction of improvements were the initial construction of the Tenant
Improvements. Landlord shall not be liable for any inconvenience or annoyance to
Tenant or its visitors, or injury to Tenant's business resulting in any way from
such damage or the repair thereof; provided however, that if such fire or other
casualty shall have damaged the Premises or common areas necessary to Tenant's
occupancy, Landlord shall allow Tenant a proportionate abatement of Rent to the
extent Landlord is reimbursed from the proceeds of rental interruption insurance
purchased by Landlord as a Basic Cost during the time and to the extent the
Premises are materially damaged and unfit for occupancy for the purposes
permitted under this Lease, and not occupied by Tenant as a result thereof.

      10.2 Landlord's Option to Repair. Notwithstanding the terms of Section
10.1 of this Lease, Landlord may elect not to rebuild and/or restore the
Premises and/or Building and instead terminate this Lease by notifying Tenant in
writing of such termination within ninety (90) days after the date of actual
discovery of damage, such notice to include a termination date giving Tenant
ninety (90) days to vacate the Premises, but Landlord may so elect only if the
Building shall be damaged by fire or other casualty or cause whether or not the
Premises are affected, and one or more of the following conditions is present:
(a) repairs cannot reasonably be completed within one hundred twenty (120) days
of the date of actual discovery of damage (when such repairs are made without
the payment of overtime or other premiums), (b) the holder of any mortgage on
the Building or ground or underlying lessor with respect to the Building shall
require that the insurance proceeds or any portion thereof be used to retire the
mortgage debt, or shall terminate the ground or underlying lease, as the case
may be; or (c) the damage is not fully covered, except for deductible amounts,
by Landlord's insurance policies.

      Notwithstanding anything to the contrary contained herein, if the Premises
is wholly or partially damaged or destroyed within the final six (6) months of
the then remaining Term of this Lease (as the same may theretofore have been
extended pursuant to this Lease), and if as a result of such damage or
destruction Tenant is, or reasonably will be, denied access or use of a material
portion of the Premises for the conduct of its business operations for a period
of ninety (90) consecutive days (or such shorter period as is then remaining in
the Term), then Landlord or


                                      -20-
<PAGE>

Tenant may, at its option, elect to terminate the Lease, by giving the other
party notice no later than sixty (60) days after the actual discovery of such
damage or destruction.

      Upon any such termination of this Lease pursuant to this Section 10.2,
Tenant shall pay Rent, properly apportioned up to such date of termination, and
both parties hereto shall thereafter be freed and discharged of all further
obligations hereunder, except as provided for in provisions of this Lease which
by their terms survive the expiration or earlier termination of the Lease Term.

      10.3 Waiver of Statutory Provisions. The provisions of this Lease,
including this Article 10, constitute an express agreement between Landlord and
Tenant with respect to any and all damage to, or destruction of, all or any part
of the Premises, the Project or any portion thereof, and any statute or
regulation of the State of California, including, without limitation, Sections
1932(2) and 1933(4) of the California Civil Code, with respect to any rights or
obligations concerning damage or destruction in the absence of an express
agreement between the parties, and any other statute or regulation, now or
hereafter in effect, shall have no application to this Lease or any damage or
destruction to all or any part of the Premises, the Project or any portion
thereof.

                                   ARTICLE 11
                                   NON-WAIVER

      No waiver of any provision of this Lease shall be implied by any failure
of Landlord to enforce any remedy on account of the violation of such provision,
even if such violation shall continue or be repeated subsequently, any waiver by
Landlord of any provision of this Lease may only be in writing, and no express
waiver shall affect any provision other than the one specified in such waiver
and that one only for the time and in the manner specifically stated. No receipt
of monies by Landlord from Tenant after the termination of this Lease shall in
any way alter the length of the Lease Term or Tenant's right of possession
hereunder or after the giving of any notice shall reinstate, continue or extend
the Lease Term or affect any notice given Tenant prior to the receipt of such
monies, it being agreed that after the service of notice or the commencement of
a suit or after final judgment for possession of the Premises, Landlord may
receive and collect any Rent due, and the payment of said Rent shall not waive
or affect said notice, suit or judgment.

                                   ARTICLE 12
                                 EMINENT DOMAIN

      12.1 Taking. If any material portion of the Project shall be taken for any
public or quasi-public purpose by any lawful power or authority by exercise of
the right of appropriation, condemnation or eminent domain, or sold to prevent
such taking to such an extent as to render untenantable the entirety of the
Premises or such a material portion of the Premises that Tenant's operation from
the remainder of the Premises is not reasonably practicable as reasonably
determined by the parties, either party shall have the right to terminate this
Lease effective as of the date possession is required to be surrendered to said
authority by written notice to the other party by the effective date of such
taking. If all or any part of the Premises shall be taken, and if such taking is
permanent, the term of this Lease shall automatically terminate with respect to
the part of the Premises so taken as of the date when the possession of such
part is required. Tenant shall not assert any claim against Landlord or the
taking authority for any compensation because of such taking, other than a claim
for any separate award attributable to the value of any personal property or
trade fixtures of Tenant which are taken, costs of Tenant's relocation, and
Tenant hereby assigns to Landlord all of Tenant's interest in, and Landlord
shall be entitled to receive, the entire amount of any other award without
deduction for any estate or interest of Tenant (including, without limitation,
any award attributable to the value of the remaining Term of this Lease). If
neither Tenant nor Landlord so elects to terminate, Landlord shall, to the
extent of proceeds received, commence to restore the Premises to substantially
their same condition prior to such partial taking, and a proportionate abatement
shall be made to Tenant for the Monthly Base Rent and Tenant's obligation for
payment of Tenant's Expenses Excess corresponding to the time during which, and
to the part of the Premises of which, Tenant shall be so deprived on account of
such taking and restoration; provided that if during the progress of Landlord's
restoration work the balance of the Premises cannot reasonably be used by Tenant
for the operation of its business, then Monthly Base Rent and Tenant's Expenses
Excess shall abate until that remaining portion of the Premises is again usable
by Tenant. Nothing contained in this Section 12.1 shall be deemed to give
Landlord any interest in any award made to Tenant for the taking of Tenant's
personal property and trade fixtures or for Tenant's costs of relocation.


                                      -21-
<PAGE>

      12.2 Temporary Taking. In the event of a taking of the Premises or any
part thereof for temporary use, (i) this Lease shall be and remain unaffected
thereby and Rent shall not abate, and (ii) Tenant shall be entitled to receive
for itself such portion or portions of any award made for such use with respect
to the period of the taking which is within the Term, provided that if such
taking shall remain in force at the expiration of the Term or earlier
termination of this Lease, Tenant shall then pay to Landlord a sum equal to the
reasonable cost of performing Tenant's obligations under Section 7.4 with
respect to surrender of the Premises and upon such payment shall be excused from
such obligations. For purposes of this Section 12.2, a temporary taking shall be
defined as a taking for a period of twelve (12) months or less.

      12.3 Certain Waivers. Landlord and Tenant hereby waive the provisions of
California Code of Civil Procedure Sections 1265.110 through 1265.160 to the
extent that such provisions are inconsistent with this Lease.

                                   ARTICLE 13
                            ASSIGNMENT AND SUBLETTING

      13.1 Transfers. Tenant shall not, without the prior written consent of
Landlord, which consent shall not be unreasonably withheld (subject to the
provisions of this Article 13) assign this Lease or sublet all or any part of
the Premises or permit the use of the Premises by any persons other than Tenant
and its employees, agents and licensees, whether by operation of law or
otherwise (all of the foregoing are hereinafter sometimes referred to
collectively as "Transfers" and any person to whom any Transfer is made or
sought to be made is hereinafter sometimes referred to as a "Transferee"). In
addition, except for any of the foregoing described Transfers made with the
prior consent of Landlord in accordance herewith, Tenant shall not, without the
prior written consent of Landlord, which consent may be granted or withheld in
Landlord's sole and absolute discretion, mortgage, pledge, hypothecate,
encumber, or permit any lien to attach to, or otherwise transfer, this Lease or
any interest hereunder, by operation of law or otherwise. If Tenant shall desire
Landlord's consent to any Transfer, Tenant shall notify Landlord in writing,
which notice (the "Transfer Notice") shall include:

            (a) the proposed effective date of the Transfer, which shall not be
      less than forty-five (45) days nor more than one hundred eighty (180) days
      after the date of delivery of the Transfer Notice;

            (b) a description of the portion of the Premises to be transferred
      (the "Subject Space");

            (c) all of the terms of the proposed Transfer and the consideration
      therefor, including a calculation of the "Transfer Premium," as that term
      is defined in Section 13.4 below, in connection with such Transfer, the
      name and address of the proposed Transferee, and a copy of all existing
      and/or proposed documentation pertaining to the proposed Transfer,
      including all existing operative documents to be executed to evidence such
      Transfer or the agreements incidental or related to such Transfer; and,

            (d) current financial statements of the proposed Transferee
      certified by an officer, partner or owner thereof, and any other
      information required by Landlord, which will enable Landlord to determine
      the financial responsibility, character, and reputation of the proposed
      Transferee, nature of such Transferee's business and proposed use of the
      Subject Space, and such other information as Landlord may reasonably
      require. Any Transfer made without Landlord's prior written consent or not
      in compliance with this Article 13 shall, at Landlord's option, be null,
      void and of no effect, and shall, at Landlord's option, constitute a
      default by Tenant under this Lease.

      Tenant shall, within thirty (30) days after written request by Landlord,
reimburse Landlord for all reasonable costs and expenses (including reasonable
attorneys' fees) incurred by Landlord in connection with its review of a
proposed Transfer.

      13.2 Landlord's Consent. Landlord shall not unreasonably withhold its
consent to any proposed Transfer of the Subject Space to the Transferee on the
terms specified in the Transfer Notice. The parties hereby agree that it shall
be reasonable under this Lease and under any applicable law for Landlord to
withhold consent to any proposed Transfer where one or more of the following
apply:


                                      -22-
<PAGE>

            (a) The Transferee is of a character or reputation or engaged in a
      business which is not consistent with the quality of the Building;

            (b) The Transferee intends to use the Subject Space for purposes
      which are not permitted hereunder;

            (c) The Transferee is either a governmental agency or
      instrumentality thereof;

            (d) The Transfer will result in more than a reasonable and safe
      number of occupants per floor;

            (e) The Transferee is not a party of reasonable financial worth
      and/or financial stability in light of the responsibilities involved under
      the Lease on the date consent is requested;

            (f) The proposed Transfer would cause Landlord to be in violation of
      another lease or agreement to which Landlord is a party, or would give an
      occupant of the Project a right to cancel its lease;

            (g) The terms of the proposed Transfer will allow the Transferee to
      exercise any right of renewal, right of expansion, right of first offer,
      or any other similar right held by Tenant (or will allow the Transferee to
      occupy space leased by Tenant pursuant to any such right); or

            (h) With respect to a Transfer proposed to be entered into during
      the first year of the Term of this Lease, the rent proposed to be paid by
      the Transferee is less than the Rent payable by Tenant under this Lease.

      If Landlord consents to any Transfer pursuant to the terms of this Section
13.2, Tenant may within six (6) months after Landlord's consent, but not later
than the expiration of said six-month period, enter into such Transfer of the
Premises or portion thereof, upon substantially the same terms and conditions as
are set forth in the Transfer Notice furnished by Tenant to Landlord pursuant to
Section 13.1 of this Lease, provided that if there are any changes in the terms
and conditions for those specified in the Transfer Notice such that (i) Landlord
would initially have been entitled to refuse its consent to such Transfer under
this Section 13.2, or (ii) which would cause the proposed Transfer to be more
favorable to the Transferee than the terms set forth in Tenant's original
Transfer Notice, Tenant shall again submit the Transfer to Landlord for its
approval and other action under this Article 13.

      13.3 Landlord's Option as to Subject Space. [Intentionally omitted.]

      13.4 Transfer Premium. If Landlord consents to a Transfer, as a condition
thereto which the parties hereby agree is reasonable, Tenant shall pay to
Landlord fifty percent (50%) of any "Transfer Premium," (as that term is
hereinafter defined) received by Tenant from such Transferee. "Transfer Premium"
shall mean all rent, additional rent or other consideration payable by such
Transferee in excess of the Rent and Additional Rent payable by Tenant under
this Lease, on a per square foot of Rentable Area basis if less than all of the
Premises is transferred, after deducting the reasonable expenses incurred by
Tenant for (i) any changes, alterations and improvements to the Premises in
connection with the Transfer or contributions to the cost thereof and (ii) any
brokerage commissions, reasonable attorneys' fees and reasonable advertising and
marketing costs reasonably incurred by Tenant in connection with the Transfer.
"Transfer Premium" shall also include, but not be limited to, key money and
bonus money paid by Transferee to Tenant in connection with such Transfer, and
any payment in excess of fair market value for services rendered by Tenant to
Transferee or for assets, fixture, inventory, equipment or furniture transferred
by Tenant to Transferee in connection with such Transfer.

      13.5 Effect of Transfer. If Landlord consents to a Transfer, (i) the terms
and conditions of this Lease shall in no way be deemed to have been waived or
modified, (ii) such consent shall not be deemed consent to any further Transfer
by either Tenant or a Transferee, (iii) Tenant shall deliver to Landlord,
promptly after execution, an original executed copy of all documentation
pertaining to the Transfer in form reasonably acceptable to Landlord, (iv)
Tenant shall furnish upon Landlord's request a complete statement, certified by
an independent certified public accountant, or Tenant's chief financial officer,
setting forth in detail the computation of any premium Tenant has


                                      -23-
<PAGE>

derived and shall derive from such Transfer, (v) any assignee shall assume in
writing all obligations and covenants of Tenant thereafter to be performed or
observed under this Lease, and (vi) no Transfer relating to this Lease or
agreement entered into with respect thereto, whether with or without Landlord's
consent, shall relieve Tenant or any guarantor of the Lease from liability under
this Lease. Landlord or its authorized representatives shall have the right at
all reasonable times to audit the books, records and papers of Tenant relating
to any Transfer, and shall have the right to make copies thereof. If the
Transfer Premium respecting any Transfer shall be found understated, Tenant
shall, within thirty (30) days after demand, pay the deficiency and Landlord's
costs of such audit, and if understated by more than ten percent (10%), Landlord
shall have the right to cancel this Lease upon thirty (30) days' notice to
Tenant.

      13.6 Additional Transfers. For purposes of this Lease, the term "Transfer"
shall also include: (i) if Tenant is a partnership, the withdrawal or change,
voluntary, involuntary or by operation of law, of fifty percent (50%) or more of
the partners, or transfer of fifty percent (50%) or more of partnership
interests, within a twelve (12) month period, or the dissolution of the
partnership without immediate reconstitution thereof; and (ii) if Tenant is a
closely held corporation (i.e., whose stock is not publicly held and not traded
through an exchange or over the counter), the dissolution, merger, consolidation
or other reorganization of Tenant; the sale or other transfer of more than an
aggregate of fifty percent (50%) of the voting shares of Tenant (other than to
immediate family members by reason of gift or death), within a twelve (12) month
period; or the sale, mortgage, hypothecation or pledge of more than an aggregate
of fifty percent (50%) of the value of the unencumbered assets of Tenant within
a twelve (12) month period.

      13.7 Affiliate Transfers. Notwithstanding anything to the contrary
contained in this Article 13, Tenant may sublet the Premises without the need
for Landlord's prior consent if such sublease is to any parent, subsidiary or
affiliate business entity which the originally named Tenant controls, is
controlled by or is under common control with (each, an "Affiliate") provided
that: (i) at least thirty (30) days prior to such sublease, Tenant delivers to
Landlord the financial statements or other financial and background information
of the assignee or sublessee as required for other transfers; (ii) the audited
financial net worth of the sublessee as at the time of the proposed transfer is
equal to or greater than the audited net worth of Tenant as at the Commencement
Date; (iii) Tenant remains fully liable under this Lease; and (iv) unless
Landlord consents to the same, the use of the Premises set forth herein remains
unchanged. As used in this section, "control" (including, with its correlative
meanings, "controlled by" and "under common control with") shall mean
possession, directly or indirectly, of power to direct or cause the direction of
management or policies through ownership of at least 51% of the securities or
partnership or other ownership interests of the entity subject to control.

                                   ARTICLE 14
                      SURRENDER OF PREMISES; TRADE FIXTURES

      14.1 Surrender of Premises. No act or thing done by Landlord or any agent
or employee of Landlord during the Lease Term shall be deemed to constitute an
acceptance by Landlord of a surrender of the Premises unless such intent is
specifically acknowledged in a writing signed by Landlord. The delivery of keys
to the Premises to Landlord or any agent or employee of Landlord shall not
constitute a surrender of the Premises or effect a termination of this Lease,
whether or not the keys are thereafter retained by Landlord, and notwithstanding
such delivery, Tenant shall be entitled to the return of such keys at any
reasonable time upon request until this Lease shall have been properly
terminated. The voluntary or other surrender of this Lease by Tenant, whether
accepted by Landlord or not, or a mutual termination hereof, shall not work a
merger, and at the option of Landlord shall operate as an assignment to Landlord
of all subtenancies affecting the Premises.

      14.2 Removal of Tenant Property by Tenant. Upon the expiration of the
Lease Term, or upon any earlier termination of this Lease, Tenant shall quit and
surrender possession of the Premises to Landlord in as good order and condition
as when Tenant took possession and as thereafter improved by Landlord,
reasonable wear and tear and repairs which are specifically made the
responsibility of Landlord hereunder excepted. Upon such expiration or
termination, Tenant shall, without expense to Landlord, remove or cause to be
removed from the Premises all debris and rubbish, and such items of furniture,
equipment, free-standing cabinet work and other articles of personal property
owned by Tenant or installed or placed by Tenant at its expense in the Premises,
and such similar articles of any other persons claiming under Tenant, as
Landlord may, in its sole discretion, require to be removed, and Tenant shall
repair at its own expense all damage to the Premises and Project resulting from
such


                                      -24-
<PAGE>

removal. If Tenant shall fail to remove all of its property from the Premises
upon the expiration of the Term or earlier termination of this Lease for any
cause whatsoever, Landlord may, at its option, either treat such property as
being conveyed to Landlord in which case the same shall automatically and
without further action be deemed to be the sole property of Landlord, or remove
the same in any manner that Landlord shall choose, and store or dispose of said
property without liability to Tenant for loss thereof, and Tenant agrees to pay
to Landlord upon demand any and all expenses incurred in such removal, including
court costs, reasonable attorneys' fees and storage charges on such property for
any length of time that the same shall be in Landlord's possession. In the
alternative, Landlord may, at its option, sell said property, or any of the
same, in such manner as Landlord determines to be appropriate in Landlord's
reasonable business judgment, for such prices as Landlord may obtain and apply
the proceeds of such sale to any amounts due under this Lease from Tenant to
Landlord and to the expense incident to the removal and sale of such property.
Tenant waives the benefit of any statutory provisions governing the treatment by
a lessor of a lessee's personal property left in leased premises following the
expiration of the lease, in the event Tenant fails to remove all of its property
from the Premises upon the expiration of the Term or earlier termination of this
Lease, the parties hereby agreeing that the provisions of this Lease constitute
the express agreement of the parties with respect thereto and are intended to
govern such situation.

                                   ARTICLE 15
                                  HOLDING OVER

      If Tenant holds over after the expiration of the Lease Term or earlier
termination thereof, without the express consent of Landlord, such tenancy shall
be from month-to-month only, and shall not constitute a renewal hereof or an
extension for any further term, and in such case Base Rent shall be payable at a
monthly rate equal to one hundred fifty percent (150%) of the Base Rent
applicable during the last rental period of the Lease Term under this Lease.
Such month-to month tenancy shall be subject to every other term, covenant and
agreement contained herein. Nothing contained in this Lease shall be construed
as consent by Landlord to any holding over by Tenant, and Landlord expressly
reserves the right to require Tenant to surrender possession of the Premises to
Landlord as provided in this Lease upon the expiration or other termination of
this Lease. The provisions of this Lease shall not be deemed to limit or
constitute a waiver of any other rights or remedies of Landlord provided herein
or at law. If Tenant fails to surrender the Premises upon the termination or
expiration of this Lease, in addition to any other liabilities to Landlord
accruing therefrom, Tenant shall protect, defend, indemnify and hold Landlord
harmless from all loss, costs (including reasonable attorneys' fees) and
liability resulting from such failure, including, without limiting the
generality of the foregoing, any claims made by any succeeding Tenant founded
upon such failure to surrender, and any lost profits to Landlord resulting
therefrom.

                                   ARTICLE 16
                     ESTOPPEL, SUBORDINATION AND ATTORNMENT

      16.1 Estoppel Certificate. Within ten (10) days after request therefor by
Landlord, Tenant shall execute and deliver an estoppel certificate which shall
be substantially in the form of Exhibit G attached hereto and made a part hereof
(or such other form as may be required by any mortgagee or prospective mortgagee
or purchaser of the Project or any portion thereof) and which shall contain such
other information reasonably requested by Landlord or any such mortgagee or
purchaser. Tenant's failure to deliver such statement in time shall constitute
an acceptance of the Premises and an acknowledgment by Tenant that the
statements included in the estoppel certificate are true and correct, without
exception.

      16.2 Subordination. This Lease is subject and subordinate to all present
and future ground or underlying leases of the Project or any portion thereof,
and to the lien of any mortgages or trust deeds, now or hereafter in force
against the Project or any portion thereof, if any, and to all renewals,
extensions, modifications, consolidations and replacements thereof, and to all
advances made or hereafter to be made upon the security of such mortgages or
trust deeds, unless the holders of such mortgages or trust deeds, or the lessors
under such ground leases or underlying leases, require in writing that this
Lease be superior thereto. Notwithstanding the foregoing to the contrary,
Landlord agrees to use commercially reasonable efforts to provide Tenant with
non-disturbance agreement(s) in favor of Tenant from any ground lessors,
mortgage holders or deed of trust beneficiaries under any ground lease, mortgage
or deed of trust affecting the Project which comes into existence at any time
after the date of execution of this Lease but prior to the expiration of the
Lease Term ("Future Mortgage"), which agreements shall be on such lessors',
holder's or beneficiaries' then standard form. Tenant covenants and agrees in
the event any


                                      -25-
<PAGE>

proceedings are brought for the foreclosure of any such mortgage or trust deed
or termination of a ground lease, to attorn, without any deductions or setoffs
whatsoever, to the purchaser upon any such foreclosure sale or ground lessor
upon any such termination if so requested to do so by such purchaser or ground
lessor, and to recognize such purchaser or ground lessor as the lessor under
this Lease. Tenant shall, within ten (10) days of request by Landlord, execute
an instrument substantially in the form attached hereto as Exhibit H or in such
other form as the applicable mortgagee, trust deed beneficiary, ground lessor or
underlying lessor may request and/or such further instruments or assurances as
Landlord may reasonably deem necessary to evidence or confirm the subordination
or superiority of this Lease to any such mortgages, trust deeds, ground leases
or underlying lease. Tenant hereby irrevocably authorizes Landlord to execute
and deliver in the name of Tenant any such instrument or instruments if Tenant
fails to do so, provided that such authorization shall in no way relieve Tenant
from the obligation of executing such instruments of subordination or
superiority. Tenant waives the provisions of any current or future statute, rule
or law which may give or purport to give Tenant any right or election to
terminate or otherwise adversely affect this Lease and the obligations of Tenant
hereunder in the event of any foreclosure proceeding or sale.

                                   ARTICLE 17
                               DEFAULTS; REMEDIES

      17.1 Events of Default. The occurrence of any of the following events
shall constitute an "Event of Default" on the part of Tenant without notice from
Landlord unless otherwise provided:

            (a) Vacation or Abandonment. Vacation or abandonment of the
      Premises;

            (b) Payment. Failure to pay any installment of Base Rent, Additional
      Rent or other monies due and payable hereunder upon the date when said
      payment is due, where such failure continues for a period of fifteen (15)
      days after receipt by Tenant of written notice from Landlord of such
      failure to pay when due (which notice shall be in lieu of, and not in
      addition to, any notice required under California Code of Civil Procedure
      Section 1161 or any similar successor statute);

            (c) Performance. Default in the performance of any of Tenant's
      covenants, agreements or obligations hereunder (except default in the
      payment of Rent), where such default continues for thirty (30) days after
      written notice thereof from Landlord (which notice shall be in lieu of,
      and not in addition to, any notice required under California Code of Civil
      Procedure Section 1161 or any similar successor statute); provided,
      however, that if the nature of Tenant's default is such that more than
      thirty (30) days are reasonably required for its cure, then Tenant shall
      not be deemed to be in default if Tenant shall promptly commence such cure
      within such thirty (30) day period and thereafter continuously and
      diligently prosecute such cure to completion within ninety (90) days after
      such default;

            (d) Assignment. A general assignment by Tenant for the benefit of
      creditors;

            (e) Bankruptcy. The filing of a voluntary petition by Tenant, or the
      filing of an involuntary petition by any of Tenant's creditors seeking the
      rehabilitation, liquidation or reorganization of Tenant under any law
      relating to bankruptcy, insolvency or other relief of debtors and not
      removed within ninety (90) days of filing.

            (f) Receivership. The appointment of a receiver or other custodian
      to take possession of substantially all of Tenant's assets or of the
      Premises or any interest of Tenant therein;

            (g) Insolvency or Dissolution. Tenant shall become insolvent or
      unable to pay its debts, or shall fail generally to pay its debts as they
      become due; or any court shall enter a decree or order directing the
      winding up or liquidation of Tenant or of substantially all of its assets;
      or Tenant shall take any action toward the dissolution or winding up of
      its affairs or the cessation or suspension of its use of the Premises;
      and,

            (h) Attachment. Attachment, execution or other judicial seizure of
      substantially all of Tenant's assets or the Premises or any interest of
      Tenant under this Lease.


                                      -26-
<PAGE>

      17.2 Landlord's Remedies. If an Event of Default shall occur, at any time
thereafter and without limiting Landlord in the exercise of any other right or
remedy at law or in equity, Landlord may elect any of the following remedies:

            (a) Continuation of Lease. Notwithstanding Tenant's breach of the
      Lease and abandonment of the Premises, Landlord may continue the Lease in
      full force and effect and enforce all of the Landlord's rights and
      remedies under the Lease, as provided by California Civil Code Section
      1951.4, including the right to recover rent as it becomes due, so long as
      Landlord does not terminate Tenant's right to possession. Acts of
      maintenance or preservation or efforts to relet the Premises or the
      appointment of a receiver upon initiative of Landlord to protect
      Landlord's interest under this Lease shall not constitute a termination of
      Tenant's right to possession. At any time subsequent to vacation or
      abandonment of the Premises by Tenant, Landlord may give notice of
      termination and shall thereafter have all of the rights set forth in
      Section 17.2 (b) below.

            (b) Termination. So long as the default continues, Landlord shall
      have the right to terminate this Lease by written notice to Tenant.

            (c) Possession. Following termination of the Lease under Section
      17.2(b) and without prejudice to any other remedies Landlord may have by
      reason of Tenant's default or of such termination, Landlord may then or at
      anytime thereafter: (i) peaceably re-enter the Premises, or any part
      thereof, upon voluntary surrender by Tenant or expel or remove Tenant
      therefrom and any other persons occupying them, using such legal
      proceedings as are then available; (ii) repossess and enjoy the Premises;
      or relet the Premises or any part thereof for such term or terms (which
      may be for a term extending beyond the Term) at such rental or rentals and
      upon such other terms and conditions as Landlord in its sole discretion
      shall determine, with the right to make reasonable alterations and repairs
      to the Premises; and (iii) remove all personal property therefrom, store
      such personal property at Tenant's expense and sell such property and
      apply the proceeds therefrom pursuant to applicable California law, all as
      attorney-in-fact for Tenant.

            (d) Recovery. Following termination under Section 17.2(b) above,
      Landlord shall have all the rights and remedies to recover from Tenant
      damages as provided by California Civil Code Section 1951.2 (or any
      successor law) including without limitation: (i) the worth at the time of
      the award of the unpaid Rent and other amounts which had been earned at
      the time of termination; (ii) the worth at the time of the award of the
      amount by which the unpaid Rent which would have been earned after
      termination until the time of the award exceeds the amount of such Rent
      loss that Tenant proves could have been reasonably avoided; (iii) the
      worth at the time of the award of the amount by which the unpaid Rent for
      the balance of the Lease Term after the time of award exceeds the amount
      of such Rent loss Tenant proves could be reasonably avoided; (iv) any
      other amount necessary to compensate Landlord for all detriment
      proximately caused by Tenant's failure to perform its obligations under
      this Lease or which in the ordinary course of things would be likely to
      result therefrom; and (v) at Landlord's election, such other amounts in
      addition to or in lieu of the foregoing as may be permitted from time to
      time by applicable law. The "worth at the time of the award" of the
      amounts referred to in (i) and (ii) are computed by allowing interest at
      the Interest Rate applicable to the time of award. The "worth at the time
      of the award" of the amount referred to in (iii) above shall be computed
      by discounting such amount at the discount rate of the Federal Reserve
      Bank of San Francisco at the time of award plus one percent (1%).

            (e) Receivership. Upon application by Landlord, Landlord may have a
      receiver appointed for Tenant to take possession of the Premises and to
      apply all rental collected from the Premises and to exercise all other
      rights and remedies granted to Landlord as attorney-in-fact for Tenant
      pursuant to Section 17.2(c) above.

            (f) Additional Remedies. In addition to the foregoing remedies, so
      long as this Lease is not terminated, Landlord shall have the right to
      remedy any default of Tenant, to maintain or improve the Premises without
      terminating the Lease, to incur expenses on behalf of Tenant in seeking a
      new sublessee or to cause a receiver to be appointed to administer the
      Premises and new or existing subleases, and to add to the Rent payable
      hereunder all of Landlord's reasonable costs in doing so, with interest at
      the maximum


                                      -27-
<PAGE>

      rate set by statute. Landlord may pursue any and all other remedies
      available to Landlord at law or in equity, by statute or otherwise.

            (g) Other Breaches. If Tenant causes or threatens a breach of any of
      the covenants, agreements, terms or conditions contained in this Lease,
      Landlord shall be entitled to retain all sums held by Landlord for
      Tenant's account or in any account provided for herein to enjoin such
      breach or threatened breach, and to invoke any right and remedy allowed at
      law or in equity or by statute or otherwise as though re-entry, summary
      proceedings and other remedies were not provided for in this Lease.

            (h) Cumulative. Each right and remedy of Landlord provided for in
      this Lease shall be cumulative and shall be in addition to every other
      right or remedy provided for in this Lease or now or hereafter existing at
      law or in equity or by statute or otherwise. The exercise or beginning of
      the exercise by Landlord of any one or more of the rights or remedies
      provided for in this Lease, now or hereafter existing at law or in equity
      or by statute or otherwise, shall not preclude the simultaneous or later
      exercise by Landlord of any or all other rights or remedies provided for
      in this Lease or now or hereafter existing at law or in equity or by
      statute or otherwise.

      17.3 No Waiver. Notwithstanding anything to the contrary contained herein,
no failure by Landlord to insist upon the strict performance of any term hereof
or to exercise any right or remedy consequent upon a breach thereof, and no
acceptance of full or partial payment of Rent during the continuance of any such
breach shall constitute a waiver of any such breach or of any such term. Efforts
by Landlord to mitigate the damages caused by Tenant's breach of this Lease
shall not be construed to be a waiver of Landlord's right to recover damages
under this Article 17. Nothing in this Article 17 affects the right of Landlord
to be indemnified and/or held harmless by Tenant in accordance with the
provisions of this Lease for liability arising prior to the termination of this
Lease.

                                   ARTICLE 18
                                    GRAPHICS

      18.1 General. Landlord shall provide identification of Tenant's name and
suite numerals at the main entrance door to the Premises. All graphics of Tenant
visible in or from public corridors or the exterior of the Premises or Project
shall be subject to Landlord's prior written approval and shall comply with the
sign criteria established as the Project standard. Upon the expiration or
earlier termination of this Lease, Tenant shall be responsible, at its sole cost
and expense, for the removal of such signage and the repair of all damage caused
by such removal.

      18.2 Building Directory. At Landlord's cost, Tenant shall be entitled to
its proportionate share of lines on the office building directory to display
Tenant's name and location in the Project.

      18.3 Prohibited Signage and Other Items. Any signs, notices, logos,
pictures, names or advertisements which are installed and that have not been
individually approved by Landlord may be removed without notice by Landlord at
the sole expense of Tenant. Tenant may not install any signs on the exterior or
roof of the Building or the common areas of the Project. Any signs, window
coverings, or blinds (even if the same are located behind the Landlord approved
window coverings for the Building), or other items visible from the exterior of
the Premises are subject to the prior approval of Landlord, in its sole
discretion.

                                   ARTICLE 19
              LANDLORD'S RIGHT TO CURE DEFAULT; PAYMENTS BY TENANT

      19.1 Landlord's Cure. All covenants and agreements to be kept or performed
by Tenant under this Lease shall be performed by Tenant at Tenant's sole cost
and expense and without any reduction of Rent. If Tenant fails to perform any
covenant or agreement to be performed by Tenant under this Lease, Landlord shall
have the right (but not the obligation) to perform such covenant or agreement
(a) immediately, in the event of an emergency situation of imminent risk of
personal injury or material property damage, or (b) following Tenant's failure
to cure such failure to perform within the period provided for cure after
Tenant's receipt of written notice from Landlord pursuant to Section 17.1 above.
Any performance by Landlord of Tenant's obligations shall not waive or cure such


                                      -28-
<PAGE>

default, or constitute a waiver by Landlord of any right it may have based upon
any default of Tenant and shall not release Tenant from any obligations
hereunder.

      19.2 Tenant's Reimbursement. Except as may be specifically provided to the
contrary in this Lease, Tenant shall, within fifteen (15) days after delivery by
Landlord to Tenant of statements therefor, pay to Landlord the following, as
Additional Rent, together with interest at the Interest Rate: (i) sums equal to
expenditures reasonably made and obligations incurred by Landlord in connection
with the remedying by Landlord of Tenant's defaults pursuant to the provisions
of Section 19.1; (ii) sums equal to all losses, costs, liabilities, damages and
expenses referred to in Article 9 of this Lease; and (iii) sums equal to all
expenditures made and obligations incurred by Landlord in collecting or
attempting to collect the Rent or in enforcing or attempting to enforce any
rights of Landlord under this Lease or pursuant to law, including, without
limitation, all legal fees and other amounts so expended. Tenant's obligations
under this Section 19.2 shall survive the expiration or sooner termination of
the Lease Term.

                                   ARTICLE 20
                            MISCELLANEOUS PROVISIONS

      20.1 Terms. The necessary grammatical changes required to make the
provisions hereof apply either to corporations, partnerships or other entities
or individuals, men or women, as the case may require, shall in all cases be
assumed as though in each case fully expressed.

      20.2 Binding Effect. Each of the provisions of this Lease shall extend to
and shall, as the case may require, bind or inure to the benefit not only of
Landlord and of Tenant, but also of their respective successors or assigns;
provided this clause shall not permit any assignment by Tenant contrary to the
provisions of Article 13 of this Lease.

      20.3 Easements. Landlord reserves the right to: (i) alter the boundaries
of the Lot, and (ii) grant easements on the Lot and dedicate for public use
portions thereof without Tenant's consent; provided, however, that no such grant
or dedication shall materially interfere with Tenant's use of the Premises.

      20.4 No Light, Air or View Easement. Any diminution or shutting off of
light, air or view by any structure which may be erected on lands adjacent to or
in the vicinity of the Project or any temporary darkening of the windows of the
Premises or obstruction of the light or view therefrom by reason of any repairs,
improvements, maintenance or cleaning in or about the Project shall in no way
affect this Lease or impose any liability on Landlord or reduce or diminish
Tenant's obligations under this Lease.

      20.5 Authorization. If Tenant executes this Lease as a corporation,
limited liability company or partnership, then Tenant and the persons executing
this Lease on behalf of Tenant represent and warrant that Tenant is duly
qualified to do business in California and that the individuals executing this
Lease on Tenant's behalf are duly authorized to execute and deliver this Lease
on its behalf, which in the case of a corporation shall be in accordance with a
duly adopted resolution of the board of directors of Tenant, a copy of which is
to be delivered to Landlord on execution hereof, which in the case of a limited
liability company, shall be in accordance with Tenant's operating agreement and
amendments thereto, if any, copies of which are to be delivered to Landlord with
the execution hereof, and which in the case of a partnership, shall be in
accordance with Tenant's partnership agreement and amendments thereto, if any,
copies of which are to be delivered to Landlord with the execution hereof.

      20.6 Accord and Satisfaction. No payment by Tenant or receipt by Landlord
of a lesser amount than the Rent herein stipulated shall be deemed to be other
than on account of the Rent, nor shall any endorsement or statement on any check
or any letter accompanying any check or payment as Rent be deemed an accord and
satisfaction, and Landlord may accept such check or payment without prejudice to
Landlord's right to recover the balance of such Rent or pursue any other remedy
provided in this Lease.

      20.7 Peaceful Enjoyment. Subject to the other terms hereof, Tenant shall
and may peacefully have, hold and enjoy the Premises, provided that Tenant pays
the Rent and other sums herein to be paid by Tenant and performs all of Tenant's
covenants and agreements contained herein. It is understood and agreed that this
covenant


                                      -29-
<PAGE>

and any and all other covenants of Landlord contained in this Lease shall be
binding upon Landlord and its successors only with respect to breaches occurring
when Landlord has an ownership interest in the Project, and shall be binding on
Landlord's successors only with respect to breaches occurring when such
successors have an ownership interest in the Project.

      20.8 Limitation of Landlord's Liability. The obligations of Landlord under
this Lease shall not constitute personal obligations of the partners, directors,
members, officers or shareholders of Landlord, and Tenant shall look solely to
the Project and to no other assets of Landlord for satisfaction of any liability
in respect of this Lease and shall not seek recourse against the partners,
directors, members, officers or shareholders of Landlord or any of their
personal assets for such satisfaction. In no case shall Landlord be liable to
Tenant for any lost profits, damage to business, or any form of special,
indirect or consequential damage on account of any breach of this Lease or
otherwise, notwithstanding anything to the contrary contained in this Lease.

      20.9 Time, Calendar Year; Calendar Days. Time is of the essence in the
performance of all obligations under this Lease. As used in this Lease, the term
"calendar year" shall mean January 1 through December 31. Except as otherwise
expressly provided herein, all references to days in this Lease shall mean
calendar days, not working or business days; provided, however, that if a
certain date falls on a weekend or holiday, the next business day shall be
substituted for the applicable date.

      20.10 Severability. If any term or provision of this Lease, or the
application thereof to any person or circumstance, the deletion of which shall
not adversely affect the receipt of any material benefit of Landlord or Tenant,
shall be invalid, void or unenforceable to any extent, the remainder of this
Lease, and the application of such terms or provisions to other persons or
circumstances, shall not be affected, impaired or invalidated thereby and shall
be enforced to the greatest extent permitted by law.

      20.11 Applicable Law. This Lease, and the rights and obligations of the
parties hereto, shall be construed and enforced in accordance with the laws of
the State of California.

      20.12 Submission of Lease. The submission of this document for examination
and negotiation neither constitutes an offer to lease, nor a reservation of, nor
option for leasing the Premises. This document shall become effective and
binding only upon execution and delivery by Landlord. No act or omission of any
employee or agent of Landlord or of Landlord's broker or managing agent shall
alter, change or modify any of the provisions hereof.

      20.13 Rules and Regulations. At all times during the Lease Term, Tenant
shall comply with rules and regulations (and such amendments as Landlord may
reasonably adopt) for the Project as set forth in Exhibit F attached hereto and
by this reference made a part hereof ("Rules and Regulations").

      20.14 No Nuisance. Tenant shall conduct its business and control its
agents, employees, invitees and visitors in such a manner as not to create any
nuisance, or interfere with, annoy or disturb any other tenant or Landlord in
its operation of the Building.

      20.15 Broker. Landlord shall be responsible, pursuant to separate written
agreement, for the payment of the commission in connection with this Lease owing
to the brokers designated in Article 12 of the Summary. Landlord warrants that
it has had no dealing with any real estate broker or agents in connection with
the negotiation of this Lease excepting only the broker or agent designated in
Article 12 of the Summary, and that it knows of no other real estate broker or
agent who is entitled to or can claim a commission in connection with this
Lease. Landlord agrees to indemnify, defend and hold Tenant harmless from and
against any and all claims, demands, losses, liabilities, lawsuits, judgments,
and costs and expenses (including, without limitation, reasonable attorneys'
fees and expenses) with respect to any alleged leasing commission or equivalent
compensation alleged to be owing on account of Landlord's dealings with any such
other real estate broker or agent. Tenant warrants that it has had no dealing
with any real estate broker or agents in connection with the negotiation of this
Lease excepting only the broker or agent designated in Article 12 of the
Summary, and that it knows of no other real estate broker or agent who is
entitled to or can claim a commission in connection with this Lease. Tenant
agrees to indemnify, defend and hold Landlord harmless from and against any and
all claims, demands, losses, liabilities, lawsuits, judgments, and costs and
expenses (including, without limitation, reasonable attorneys' fees and
expenses) with respect to any


                                      -30-
<PAGE>

alleged leasing commission or equivalent compensation alleged to be owing on
account of Tenant's dealings with any such other real estate broker or agent.

      20.16 Modification for Lender. If, in connection with obtaining
construction, interim or permanent financing for the Project, the lender or any
ground lessor shall request reasonable modifications in this Lease as a
condition to such financing, Tenant will not unreasonably withhold, delay or
defer its consent thereto, provided that such modifications do not increase the
obligations of Tenant hereunder or materially adversely affect the leasehold
interest hereby created or Tenant's rights hereunder.

      20.17 Recording. Neither Landlord nor Tenant shall record this Lease or
any short form memorandum hereof.

      20.18 Parking Facilities.

            (a) The parking areas within the Project are available for the use
      of tenants of the Project and their visitors and customers. All parking
      rights are subject to the rules, regulations, validation and
      identification systems set forth by Landlord from time to time. Landlord
      may restrict certain portions of the Project parking areas for the
      exclusive use of one or more tenants of the Project and may designate
      other areas to be used at large only by customers and visitors of tenants
      of the Project. Landlord reserves the right to delegate the operation of
      the Project parking areas to a parking operator which shall be entitled to
      all of the obligations and benefits of Landlord.

            (b) During the Lease Term, Tenant shall have the right in common
      with other tenants of the Project to rent/use the number of unreserved
      spaces in the Project parking areas specified in the Summary; additional
      parking spaces for Tenant's customers and visitors may be allowed at
      Landlord's option, subject to availability. Notwithstanding the foregoing,
      Landlord reserves the right, from time to time, to make reasonable changes
      in, additions to and deletions from the parking areas and the purposes to
      which the same may be devoted, provided that Landlord does not permanently
      reduce the number of Tenant's parking spaces specified above.

            (c) Landlord shall have the right to cause to be removed any
      vehicles of Tenant, its customers or visitors that are parked in violation
      of this Lease or in violation of the Rules and Regulations, without
      liability of any kind to Landlord and Tenant agrees to indemnify, defend,
      protect and hold Landlord harmless from and against any and all claims,
      losses, damages, demands, costs and expenses (including without limitation
      reasonable attorney's fees and expenses) asserted or arising with respect
      to or in connection with the removal of any such automobile(s). Landlord
      shall not be liable for any claims, losses, damages, expenses or demands
      with respect to any vehicles of Tenant, its customers or visitors that are
      parked in the Project parking areas, except for such loss or damage as may
      be caused by Landlord's gross negligence or willful misconduct, and Tenant
      agrees to indemnify, defend, protect and hold Landlord harmless from and
      against any such claim, loss, damage, demand, cost or expense (including
      without limitation reasonable attorneys' fees and expenses). From time to
      time, upon request of Landlord, Tenant shall supply Landlord with a list
      of license plate numbers of all automobiles owned by its employees and
      agents granted parking privileges.

      20.19 No Merger. The voluntary or other surrender of this Lease by Tenant,
or a mutual cancellation thereof, shall not work a merger, and at the option of
Landlord shall terminate all or any existing assignments, subleases or
subtenancies, or at the option of Landlord may operate as an assignment to it of
any or all such assignments, subleases or subtenancies.

      20.20 Amendment. Except as otherwise provided herein, no subsequent
alteration, amendment, change or addition to this Lease shall be binding upon
Landlord or Tenant unless in writing and executed by Landlord and Tenant.

      20.21 Financial Statements. At any time during the Lease Term, Tenant
shall upon ten (10) days prior written notice from Landlord provide Landlord
with a current financial statement and financial statements of the two


                                      -31-
<PAGE>

(2) years prior to the current financial statement year. Such statements shall
be prepared in accordance with generally accepted accounting principles.

      20.22 Hazardous Substances; Indemnification.

            (a) Except for general office supplies typically used in an office
      area in the ordinary course of business, such as copier toner, liquid
      paper, glue, ink, and cleaning solvents, for use in the manner for which
      they were designed, in such amounts as may be normal for the office
      business operations conducted by Tenant in the Premises and for Permitted
      Hazardous Substances, neither Tenant nor its agents, employees,
      contractors, licensees, sublessees, assignees, concessionaires or invitees
      shall use, handle, store or dispose of any Hazardous Substances in, on,
      under or about the Premises or the Project. Except for Hazardous
      Substances customarily used in connection with general office uses and
      Permitted Hazardous Substances, Tenant shall not cause or permit any
      Hazardous Substance to be used, stored, generated or disposed of on or in
      the Project or the Premises by Tenant, Tenant's agents, employees,
      contractors, or invitees. If any Hazardous Substances are used, stored,
      generated, or disposed of on or in the Premises including without
      limitation those customarily used in connection with general office uses
      and any Permitted Hazardous Substances, or if the Premises become affected
      by any release or discharge of a Hazardous Substance, Tenant shall
      indemnify, defend and hold harmless Landlord from and against any and all
      claims, damages, fines, judgments, penalties, costs, liabilities, or
      losses (including, without limitation, a decrease in value of the
      Premises, damages caused by loss or restriction of rentable or usable
      space, or any damages caused by adverse impact on marketing of the space,
      and any and all sums paid for settlement of claims, attorneys' fees,
      consultant, and expert fees) arising during or after the term of this
      Lease and arising as a result of such contamination, release or discharge.
      This indemnification includes, without limitation, any and all costs
      incurred because of any investigation of the site or any clean-up,
      remediation, removal, or restoration mandated by federal, state or local
      agency or political subdivision. Without limitation of the foregoing, if
      Tenant causes or permits the presence of any Hazardous Substance on the
      Premises and the same results in any contamination, release or discharge,
      Tenant shall promptly, at its sole expense, take any and all necessary
      actions to return the Premises to the conditions existing prior to the
      presence of any such Hazardous Substance on the Premises. Tenant shall
      first obtain Landlord's approval for any such remedial action.
      Furthermore, Tenant shall immediately notify Landlord of any inquiry,
      test, investigation or enforcement proceeding by or against Tenant or the
      Project concerning the presence of any Hazardous Substance. Tenant
      acknowledges that Landlord, at Landlord's election, shall have the sole
      right, at Tenant's expense, to negotiate, defend, approve and appeal any
      action taken or order issued by any governmental authority with regard to
      any Hazardous Substance contamination for which Tenant is obligated
      hereunder.

            (b) As used herein, "Hazardous Substance" means asbestos, any
      petroleum fuel, polychlorobiphenyls ("PCBs") and any hazardous or toxic
      substance, material or waste which is or becomes regulated by any local
      governmental authority, the State of California or the United States
      government, including, but not limited to, any material or substance
      defined as a "hazardous waste", "extremely hazardous waste", "restricted
      hazardous waste", "hazardous substance", "hazardous material" or "toxic
      pollutant" under the California Health and Safety Code and/or under the
      Comprehensive Environmental Response, Compensation and Liability Act, 42,
      U.S.C. section T9901, et. seq.

            (c) Landlord hereby consents to Tenant's use of the Hazardous
      Substances described in Schedule 20.22 to this Lease (the "Permitted
      Hazardous Substances"); provided that all such Hazardous Substances are
      used in connection with Tenant's permitted use and in all cases in
      complete compliance with all federal, state and local laws governing the
      use and disposal of Hazardous Substances.

      20.23 Entire Agreement. It is understood and acknowledged that there are
no oral agreements between the parties hereto affecting this Lease and this
Lease supersedes and cancels any and all previous negotiations, arrangements,
brochures, agreements and understandings, if any, between the parties hereto or
displayed by Landlord to Tenant with respect to the subject matter thereof, and
none thereof shall be used to interpret or construe this Lease. This Lease
contains all of the terms, covenants, conditions, warranties and agreements of
the parties relating in any manner to the rental, use and occupancy of the
Premises, shall be considered to be the only agreement between the parties
hereto and their representatives and agents, and none of the terms, covenants,


                                      -32-
<PAGE>

conditions or provisions of this Lease can be modified, deleted or added to
except in writing signed by the parties hereto. All negotiations and oral
agreements acceptable to both parties have been merged into and are included
herein. There are no other representations or warranties between the parties,
and all reliance with respect to representations is based totally upon the
representations and agreements contained in this Lease. Without limiting the
generality of the foregoing, in executing and delivering this Lease, Tenant has
not relied on any representation including, but not limited to, any
representation whatsoever as to the amount of any item comprising Rent or the
amount of Rent in the aggregate or that Landlord is furnishing the same services
to other Tenants, at all, on the same level or on the same basis or any warranty
or any statement of Landlord which is not set forth herein or in one or more of
the exhibits attached hereto.

      20.24 Force Majeure. Any prevention, delay or stoppage due to strikes,
lockouts, labor disputes, acts of God, inability to obtain services, labor or
materials or reasonable substitutes therefor, governmental actions, civil
commotions, fire or other casualty, and other causes beyond the reasonable
control of the party obligated to perform, except with respect to the
obligations imposed with regard to Rent and other charges to be paid by Tenant
pursuant to this Lease (collectively, "Force Majeure"), notwithstanding anything
to the contrary contained in this Lease, shall excuse the performance of such
party for a period equal to any such prevention, delay or stoppage and,
therefore, if this Lease specifies a time period for performance of an
obligation of either party, that time period shall be extended by the period of
any delay in such party's performance caused by Force Majeure.

      20.25 Waiver of Redemption. Tenant hereby waives for Tenant and for all
those claiming under Tenant all right now or hereafter existing to redeem by
order or judgment of any court or by any legal process or writ, Tenant's right
of occupancy of the Premises after any termination of this Lease.

      20.26 Joint and Several. If there is more than one Tenant, the obligations
imposed upon Tenant under this Lease shall be joint and several.

      20.27 Notices. All notices, demands, statements, approvals or
communications (collectively, "Notices") given or required to be given by either
party to the other hereunder shall be in writing, shall be sent by United States
certified or registered mail, postage prepaid, return receipt requested, or
delivered personally (i) to Tenant at the appropriate address set forth in
Section 5 of the Summary, or to such other place as Tenant may from time to time
designate in a Notice to Landlord; or (ii) to Landlord at the addresses set
forth in Section 3 of the Summary, or to such other firm or to other place as
Landlord may from time to time designate in a Notice to Tenant. Any Notice will
be deemed given on the date it is mailed as provided in this Section 20.27 or
upon the date personal delivery is made or attempted to be made. If Tenant is
notified of the identity and address of Landlord's mortgagee or ground or
underlying lessor, Tenant shall give to such mortgagee or ground or underlying
lessor written notice of any default by Landlord under the terms of this Lease
by registered or certified mail, and such mortgagee or ground or underlying
lessor shall be given a reasonable opportunity to cure such default prior to
Tenant's exercising any remedy available to Tenant.

      20.28 Attorneys' Fees. If either party commences litigation against the
other for the specific performance of this Lease, for damages for the breach
hereof or otherwise for enforcement of any remedy hereunder, the parties hereto
agree to and hereby do waive any right to a trial by jury and, in the event of
any such commencement of litigation, the prevailing party shall be entitled to
recover from the other party such costs and actual professional fees such as
appraisers and accountants and reasonable attorneys' fees as may have been
incurred, including any and all costs and fees incurred in enforcing, perfecting
and executing such judgment.

      20.29 Independent Covenants. This Lease shall be construed as though the
covenants herein between Landlord and Tenant are independent and not dependent
and Tenant hereby expressly waives the benefit of any statute to the contrary
and agrees that if Landlord fails to perform its obligations set forth herein,
Tenant shall not be entitled to make any repairs or perform any acts hereunder
at Landlord's expense or to any set-off of the Rent or other amounts owing
hereunder against Landlord; provided, however, that the foregoing shall in no
way impair the right of Tenant to commence a separate action against Landlord
for any violation by Landlord of the provisions hereof so long as notice is
first given to Landlord and any holder of a mortgage or deed of trust covering
the Building, Project or any portion thereof, of whose address Tenant has
theretofore been notified, and an opportunity is granted to Landlord and such
holder to correct such violations as provided above.


                                      -33-
<PAGE>

      20.30 Project Name and Signage. Landlord shall have the right at any time
to change the name of the Project and to install, affix and maintain any and all
signs on the exterior and on the interior of the Project as Landlord may, in
Landlord's sole discretion, desire.

      20.31 Transportation Management. Tenant shall fully comply with all
present or future programs intended to manage parking, transportation or traffic
in and around the Project, and in connection therewith, Tenant shall take
responsible action for the transportation, planning and management of all
employees located at the Premises by working directly with Landlord, any
governmental transportation management organization or any other
transportation-related committees or entities. Such programs may include,
without limitation: (i) restrictions on the number of peak-hour vehicle trips
generated by Tenant, (ii) increased vehicle occupancy; (iii) implementation of
an in-house ride-sharing program and an employee transportation coordinator;
(iv) working with employees and any Project or area-wide ride-sharing program
manager; (v) instituting employer-sponsored incentives (financial or in-kind) to
encourage employees to ride-share; and (vi) utilizing flexible work shifts for
employees. Costs incurred by Landlord in connection with any such transportation
management shall be includable in Operating Expenses.

      20.32 No Discrimination. Tenant covenants by and for itself, its heirs,
executors, administrators and assigns, and all persons claiming under or through
Tenant, and this Lease is made and accepted upon and subject to the following
conditions: that there shall be no discrimination against or segregation of any
person or group of persons, on account of race, color, creed, sex, religion,
marital status, ancestry or national origin in the leasing, subleasing,
transferring, use or employment of the Premises, nor shall Tenant itself, or any
person claiming under or through Tenant, establish or permit such practice or
practices of discrimination or segregation with reference to the selection,
location, number, use or occupancy of tenants, lessees, sublessees, subtenants
or vendees in the Premises.


                                      -34-
<PAGE>

      IN WITNESS WHEREOF, Landlord and Tenant have caused this Lease to be
executed the day and date first above written.

"LANDLORD":

HAMILTON MARIN, LLC,
a California limited liability company

By:   Barker Pacific Group, Inc.,
      a Delaware corporation,
      its Authorized Signatory


      By: /s/ MICHAEL D. BARKER
          ---------------------------
               Michael D. Barker,
               Managing Director

"TENANT":

SPATIALIGHT, INC., a New York corporation



By: /s/ ROBERT A. OLINS
    -----------------------------------------

Print Name:  Robert A. Olins
            ---------------------------------

Its: Chief Executive Officer
     ----------------------------------------

By:
    -----------------------------------------

Print Name:
            ---------------------------------

Its:
     ----------------------------------------


                                      -35-
<PAGE>

                                    EXHIBIT A

                                HAMILTON LANDING

                        OUTLINE OF FLOOR PLAN OF PREMISES

                          (TO BE PROVIDED BY LANDLORD)


                               EXHIBIT A - PAGE 1
<PAGE>

                                    EXHIBIT B

                                HAMILTON LANDING

                                LEGAL DESCRIPTION

All the certain real property located in the City of Novato, County of Marin,
State of California, described as follows:

PARCEL ONE (Hangars 5 & 6):

Being a portion of Lots 5 and 8, as shown upon that certain Map entitled "Map of
Hamilton Field, a Subdivision of the Lands of New Hamilton Partnership, City of
Novato, County of Marin, State of California", filed for record December 18,
1995 in Volume 21 of Maps, at Page 45, Marin County Records, as amended by that
certain Lot Line Adjustment evidenced by that certain Grant Deed dated August 3,
1999, and filed for record September 2, 1999, as Instrument No. 1999-0066626,
Marin County Records, being more particularly described as follows:

BEGINNING at the Southerly corner of said Lot 8, also being the Westerly corner
of Lot 7 of said map; thence along the Southeast line of said Lot 8, also being
the Northwest line of said Lot 7, North 59 degrees55'00"East, 193.56 feet to the
point of beginning for this described parcel; thence leaving the Southeast line
of said Lot 8, North 30 degrees05'34" West, 452.10 feet to the Northerly line of
said Lot 8, also being the Southerly line of Lot 9, as said Lot 9 is shown on
said map; thence along the line common to said Lots 8 and 9 and Lots 4 and 5,
North 59 degrees55'00" East 339.44 feet to the Northerly corner of said Lot 5,
also being the Easterly corner of said Lot 4; thence along the Northeast line of
said Lot 5, South 29 degrees56'04" East 452.10 feet to the Southeast corner of
said Lot 5, also being the Northwest corner of Lot 6 as said Lot 6 is shown on
said map; thence along the common line of said Lots 5 and 6 and said Lots 7 and
8, South 59 degrees55'00" West 338.19 feet to the point of beginning.

Reserving therefrom a non-exclusive easement for access and utility purposes
over a strip of land, 30 feet wide and lying Southeasterly of and contiguous to
the Northwesterly line of the above described parcel.

Said easement to be appurtenant to and for the benefit of Lot 4, map above
referred to.

PARCEL TWO (Hangars 3 & 4):

Being a portion of Lots 6 and 7, as shown upon that certain Map entitled "Map of
Hamilton Field, a Subdivision of the Lands of New Hamilton Partnership, City of
Novato, County of Marin, State of California", filed for record December 18,
1995 in Volume 21 of Maps, at Page 45, Marin County Records, as amended by that
certain Lot Line Adjustment evidenced by that certain Grant Deed dated August 3,
1999, and filed for record September 2, 1999, as Instrument No. 1999-0066627,
Marin County Records, being more particularly described as follows:

Beginning at the Southerly corner of Lot 7, of said map, also being the Westerly
corner of Parcel A, as said Parcel A is shown upon that certain Map entitled,
"Record of Survey of a Portion of the Hamilton Air Force Military Reservation
Map", filed for record January 24, 1983 in Book 18 of Surveys, at Page 21, Marin
County Records; thence along the Southeast line of said Lot 7, North 59
degrees55'00" East, 194.80 feet to the point of beginning for this described
parcel; thence leaving the Southeast line of said Lot 7, North 30 degrees05'34"
West, 452.10 feet to the Northwest line of said Lot 7, also being the Southeast
line of Lot 8, as shown on said "Map of Hamilton Field"; thence along the line
common to said Lots 7 and 8 and Lots 5 and 6, North 59 degrees55'00" East 338.19
feet to the Northerly corner of said Lot 6 also being the Easterly corner of
said Lot 5; thence along the Northeast line of said Lot 6, South 29
degrees56'04" East 452.10 feet to the Southeast corner of said Lot 6, also being
the Northwest line of said Parcel A; thence along the common line of said Lots 6
and 7 with said Parcel A, South 59 degrees55'00" West 336.95 feet to the point
of beginning.


                               EXHIBIT B - PAGE 1
<PAGE>

PARCEL THREE:

Being a portion of Lot 8, as shown upon that certain Map entitled "Map of
Hamilton Field, a Subdivision of the Lands of New Hamilton Partnership, City of
Novato, County of Marin, State of California", filed for record December 18,
1995 in Volume 21 of Maps, at Page 45, Marin County Records, as amended by that
certain Lot Line Adjustment evidenced by that certain Grant Deed dated August 3,
1999, and filed for record September 2, 1999, as Instrument No. 1999-0066629,
Marin County Records, being more particularly described as follows:

BEGINNING at the Southerly corner of said Lot 8, also being the Westerly corner
of Lot 7 of said map; thence along the Southeast line of said Lot 8, also being
the Northwest line of said Lot 7, North 59 degrees55'00" East 193.56 feet to the
point of beginning for this described parcel; thence leaving the Southeast line
of said Lot 8, North 30 degrees05'34" West 452.10 feet to the Northwest line of
said Lot 8, also being the Southeast line of Lot 9, as shown on said map; thence
along the line common to said Lots 8 and 9, South 59 degrees55'00" West 192.31
feet to the Westerly corner of said Lot 8, also being the Southerly corner of
said Lot 9; thence along the Southwest line of said Lot 8, South 29
degrees56'04" East 452.10 feet to the Southeast corner of said Lot 8, also being
the Northwest corner of said Lot 7; thence along the common line of said Lots 7
and 8, North 59 degrees55'00" East 193.56 feet to the point of beginning.

EXCEPTING THEREFROM Parcel 'D' as shown on said "Map of Hamilton Field".

Reserving therefrom a non-exclusive easement for access and utility purposes
over a strip of land 30 feet wide and lying Southeasterly of and contiguous to
the Northwesterly line of the above described parcel.

Said easement to be appurtenant to and for the benefit of Lots 4 and 9, map
above referred to.

PARCEL FOUR:

A NON-EXCLUSIVE easement for access and utility purposes over a strip of land 25
feet wide and lying Southeasterly of and contiguous to the Southeasterly line of
Parcel Three above described, as created in the deed recorded November 9, 1999,
as Instrument No. 1999-81106, Marin County Records.

SAID EASEMENT to be appurtenant to and for the benefit of Parcels One, Two and
Three herein described.

PARCEL FIVE:

Those portions of the non-exclusive Reciprocal Easements for parking, pedestrian
and vehicular ingress and egress, utility and other purposes, all as more
particularly described in Article 4 of the Declaration and Establishment of
Protective Covenants, Conditions and Restrictions and Grant of Easements,
recorded November 9, 1999, as Instrument No. 1999-81105, Marin County Records,
lying outside the boundaries of the property described in Parcels One, Two and
Three.


                               EXHIBIT B - PAGE 2
<PAGE>

                                    EXHIBIT C

                                HAMILTON LANDING

                                   WORK LETTER

      This Work Letter shall set forth the terms and conditions relating to the
construction of the Tenant improvements in the Premises. This Work Letter is
essentially organized chronologically and addresses the issues of the
construction of the Premises, in sequence, as such issues will arise during the
actual construction of the Premises. All capitalized terms used but not defined
herein shall have the meanings given such terms in this Lease. All references in
this Work Letter to Articles or Sections of "this Lease" shall mean the relevant
portion of Articles 1 through 20 of this Lease to and of which this Work Letter
forms a part. All references in this Work Letter to Sections of "this Work
Letter" shall mean the relevant portion of Sections 1 through 6 of this Work
Letter.

                                    AGREEMENT

                                    SECTION 1

                            BASE, SHELL AND CORE WORK

      The "Base, Shell and Core Work" described on Schedule 1 attached to this
Exhibit C and incorporated herein by this reference has been and/or will be
performed by Landlord at Landlord's sole cost and expense. For all purposes of
the Lease of which this Exhibit is a part, (a) the substantial completion of the
Base, Shell and Core Work shall be deemed to occur on such date as Landlord
delivers notice to Tenant that the Base, Shell and Core Work has been
substantially completed in accordance herewith; and (b) the Base, Shell and Core
Work shall be deemed to be "substantially completed" at such time as the Base,
Shell and Core Work has been completed to such a level that the incomplete
nature of the Base, Shell and Core Work shall not materially adversely affect
the operation of Tenant's business from the Premises. Landlord shall diligently
prosecute the Base, Shell and Core Work to completion following such substantial
completion. The parties shall reasonably cooperate to avoid delay or increased
costs to either party as a result of the completion of the Base, Shell and Core
Work concurrent with the performance of the Tenant Improvements.

                                    SECTION 2

              PLANS AND SPECIFICATIONS FOR THE TENANT IMPROVEMENTS

      2.1 Final Space Plan. As used in the Lease of which this Exhibit is a
part, the "Tenant Improvements" shall mean certain improvements to be
permanently affixed to the Premises and shall not include any of Tenant's
furniture, trade fixtures, telephone, telecommunications, computer or date
cabling or equipment, or other equipment or personal property. Prior to the
execution of this Lease, Landlord and Tenant have approved that certain
preliminary space plan respecting the construction of the Tenant Improvements in
the Premises, a copy of which is included as Exhibit D to the Lease (the
"Preliminary Space Plan"). Promptly following the execution of this Lease, to
the extent not theretofore approved by the parties, Landlord shall cause such
architect as Landlord may reasonably designate to prepare and submit to Tenant
for its approval a final space plan for the Tenant Improvements consistent with
the Preliminary Space Plan which shall include specifications sufficient to
allow preliminary estimated pricing for the costs of construction of the Tenant
Improvements (the "Final Space Plan"). Tenant's approval of the Final Space Plan
shall not be unreasonably withheld, conditioned or delayed and shall be deemed
approved if, within ten (10) days following Tenant's receipt of the Final Space
Plan, Tenant fails to deliver written notice to Landlord identifying the basis
for its disapproval thereof in reasonable detail and providing suggested
revisions thereto. If Tenant so timely disapproves the Final Space Plan, then
the parties shall promptly meet and resolve any differences as to the Final
Space Plan. If the Final Space Plan has heretofore been approved by the parties,
notwithstanding anything to the contrary contained herein, Exhibit D to the
Lease shall be a copy of such Final Space Plan. Promptly following the approval
of the Final Space Plan, Landlord shall select a contractor to perform the work
of the Tenant Improvements based upon a negotiated contract using the Final
Space Plan as the basis of the estimated costs of the Tenant Improvements.


                               EXHIBIT C - PAGE 1
<PAGE>

      2.2 Construction Drawings. Promptly following the approval of the Final
Space Plan, to the extent not theretofore approved by the parties, Landlord
shall cause its Richard Pollack Associates (or such other architect as Landlord
may reasonably designate) to prepare and submit to Tenant for its approval final
construction drawings for the Tenant Improvements consistent with the approved
Final Space Plan (the "Construction Drawings"). Tenant's approval of the
Construction Drawings shall not be unreasonably withheld, conditioned or delayed
and shall be deemed approved if, within ten (10) days following Tenant's receipt
of the Construction Drawings, Tenant fails to deliver written notice to Landlord
identifying the basis for its disapproval thereof in reasonable detail and
providing suggested revisions thereto. If Tenant so timely disapproves the
Construction Drawings, then the parties shall promptly meet and resolve any
differences as to the Construction Drawings. Unless otherwise approved by
Landlord, the extent that the finishes and specifications for the Tenant
improvements shall be in accordance with the specifications for the Building's
standard improvement package items, as determined by Landlord.

      2.3 Changes to Construction Drawings. Tenant shall make no changes or
modifications to the approved Construction Drawings without the prior written
consent of Landlord, which consent may be withheld in Landlord's sole discretion
if such change or modification would: (i) directly or indirectly delay the
"Substantial Completion", as that term is in defined Section 6 below, of the
Tenant Improvements; (ii) increase the cost of designing or constructing the
Tenant Improvements above the cost of the Tenant Improvements depicted in the
Plans unless Tenant agrees to be solely responsible such costs as an increase to
the "Over-Allowance Amount" (as hereinafter defined); (iii) be likely to
adversely affect Building systems, the structure of the Building or the safety
of the Building and/or its occupants; (iv) be likely to impair Landlord's
ability to furnish services to Tenant or other tenants in the Building; (v)
increase the cost of operating the Building; (vi) violate any governmental laws,
rules or ordinances, (vii) be of a quality lower than the quality of the
standard improvement package items for the Building; and/or (iv) require any
changes to the Base, Shell and Core Work.

      2.4 Limitation on Landlord's Liability. Landlord's submittal and/or
approval of the Preliminary Space Plan, the Final Space Plan and/or the
Construction Drawings as set forth in this Section 2, shall not imply Landlord's
review of the same, or obligate Landlord to review the same, for quality,
design, compliance with codes or other like matters. Accordingly,
notwithstanding that the Preliminary Space Plan, the Final Space Plan and/or the
Construction Drawings have been submitted, reviewed and/or approved by Landlord
or its space planner, architect, engineers and consultants, and notwithstanding
any advice or assistance which may have been or may be rendered to Tenant by
Landlord or Landlord's space planner, architect, engineers, and consultants,
Landlord shall have no liability whatsoever in connection therewith and shall
not be responsible for any omissions or errors contained in the Preliminary
Space Plan, the Final Space Plan and/or the Construction Drawings, and Tenant's
waiver and indemnity set forth in the Lease shall specifically apply to the
Preliminary Space Plan, the Final Space Plan and the Construction Drawings.

                                    SECTION 3

            CONSTRUCTION, COSTS, ALLOWANCE AND OVER-ALLOWANCE AMOUNT

      3.1 Contractor. Landlord shall select one contractor ("Landlord's Choice")
and Tenant shall select one contractor (collectively, the "Bidding Contractors")
to be reasonably approved by Landlord to bid on the construction of the Tenant
Improvements and Tenant shall deliver notice of its selection of its Bidding
Contractor to Landlord on or before execution and delivery of the Lease by
Tenant. Landlord shall solicit the bids from the Bidding Contractors limited to
their fee and general condition (the "Preliminary Bid"). If Landlord's Choice
does not have the lowest Preliminary Bid, Landlord shall have the right to give
Landlord's Choice an additional period in which to modify its bid to match the
lowest Preliminary Bid. After Landlord's receipt of the Preliminary Bids
(including any revised bid from Landlord's Choice), Landlord shall provide
copies of those bids to Tenant. On the second business day after delivery of the
Preliminary Bids to Tenant, representatives of Landlord and Tenant shall meet by
telephone or in person to discuss the Preliminary Bid. If Landlord's Choice is
the lowest bidder or has matched the lowest bidder, Landlord's Choice shall be
the contractor (the "Contractor") to construct the Tenant Improvements. If
Landlord's Choice is not the lowest bidder or has not matched the lowest bid,
then the Contractor shall be the Bidding Contractor mutually agreed upon by
Landlord and Tenant acting reasonably and in good faith and if Landlord and
Tenant are unable to agree upon the Contractor in that circumstance within five
business days after delivery of the Preliminary Bids, then the Contractor shall
be Bidding Contractor with the lowest Preliminary Bid; provided, however, that
in lieu of proceeding with that Contractor, Landlord may elect to terminate the
Lease.


                               EXHIBIT C - PAGE 2
<PAGE>

      3.2 Construction of the Tenant Improvements. Landlord and Tenant hereby
agree that Landlord shall cause the Contractor to construct the Tenant
Improvements as depicted on the Construction Drawings; provided, however, in the
event that Tenant shall request any changes or substitutions to any of the
Construction Drawings, which changes or substitutions are approved by Landlord,
and such changes and/or substitutions result in increased Tenant Improvements
Costs, then Tenant shall pay such excess costs to Landlord in cash within three
(3) days after Landlord's request therefor as an increase in the Over-Allowance
Amount.

      3.3 Tenant Improvements Costs. The cost of the Tenant Improvements
(collectively, the "Tenant Improvement Costs") shall include, without
limitation, the cost of: architectural and engineering fees (including, without
limitation, in the preparation of the Preliminary Space Plan, the Final Space
Plan and the Construction Drawings); permits, approvals and other governmental
fees; labor, material, equipment and supplies; construction fees and other
amounts payable to contractors or subcontractors; taxes; off-site improvements
(if any are required in connection with the Tenant Improvements); preparation of
the Premises for construction of the Tenant Improvements; taxes; filing and
recording fees; premiums for insurance and bonds; attorneys' fees; financing
costs; and all other costs expended or to be expended in the construction of the
Tenant Improvements; and an administration fee (the "Administration Fee")
payable to Landlord in an amount equal to three percent (3%) of the total of the
Tenant Improvements Costs other than such Administration Fee.

      3.4 Allowance. Tenant shall be entitled to a one-time tenant improvement
allowance (the "Allowance") in the amount of Thirty-One Dollars ($31.00) per
square foot of usable area in the Premises for the costs relating to the initial
design and construction of the Tenant Improvements.

      3.5 Over-Allowance Amount. After the Construction Drawings are signed by
Landlord and Tenant, Contractor shall solicit bids from at least two (2)
subcontractors in each major trade for the construction of the Tenant
Improvements and shall provide Tenant with a cost proposal (the "Cost Proposal")
in accordance with the Construction Drawings, which cost proposal shall include,
as nearly as possible, the cost of all Tenant Improvement Costs to be incurred
by Tenant in connection with the design and construction of the Tenant
Improvements. Tenant's approval of the Cost Proposal shall not be unreasonably
withheld, conditioned or delayed and shall be deemed approved if, within ten
(10) days following Tenant's receipt of the Cost Proposal, Tenant fails to
deliver written notice to Landlord identifying the basis for its disapproval
thereof in reasonable detail and providing suggested revisions thereto. If
Tenant so timely disapproves the Cost Proposal, then the parties shall promptly
meet and resolve any differences as to the Cost Proposal. Upon Tenant's approval
of the Cost Proposal in accordance herewith, Landlord shall be deemed authorized
by Tenant to purchase materials for and perform the work of the Tenant
Improvements. The date by which Tenant must approve and deliver the Cost
Proposal to Landlord is referred to herein as the "Cost Proposal Delivery Date".
On the Cost Proposal Delivery Date, Tenant shall deliver to Landlord cash in an
amount (the "Over-Allowance Amount") equal to the difference between (1) the
amount of the Cost Proposal and (2) the amount of the Allowance (less any
portion of the Allowance already disbursed by Landlord, or in the process of
being disbursed by Landlord, on or before the Cost Proposal Delivery Date). The
Over-Allowance Amount held by Landlord shall not bear interest and shall be
disbursed by Landlord prior to the disbursement of any then remaining portion of
the Allowance, and such disbursement shall be pursuant to the Landlord's
customary construction disbursement procedures. In the event that after the Cost
Proposal Date, any revisions, changes, or substitutions shall be made to the
Construction Drawings or the Tenant Improvements, any additional costs which
arise in connection with such revisions, changes or substitutions or any other
additional costs shall be paid by Tenant to Landlord immediately upon Landlord's
request as an addition to the Over-Allowance Amount. Following completion of the
Tenant Improvements, Landlord shall deliver to Tenant a summary of the Tenant
Improvements Costs in reasonable detail. If following the completion of the
Tenant Improvements, it is determined by Landlord that actual Tenant
Improvements Costs in excess of the Allowance were other than the amount
theretofore paid by Tenant to Landlord as the Over-Allowance Amount pursuant
hereto, then within fifteen (15) days thereafter, the parties shall make such
adjustment payment or refund, as applicable, so that Tenant shall have paid to
Landlord the full amount by which the actual Tenant Improvements Costs exceed
the Allowance.


                               EXHIBIT C - PAGE 3
<PAGE>

                                    SECTION 4

                     CONTRACTOR'S WARRANTIES AND GUARANTIES

      Landlord will, upon completion of the Tenant Improvements and Tenant's
acceptance of the Premises, assign to Tenant all warranties and guaranties by
the Contractor relating to the Tenant Improvements, and Tenant hereby waives all
claims against Landlord relating to, or arising out of the construction of, the
Tenant Improvements.

                                    SECTION 5

                               TENANT'S COVENANTS

      Tenant shall use its good faith efforts to cooperate with Landlord to
cause a Notice of Completion to be recorded in the Office of the Recorder of the
County of Marin in accordance with section 3093 of the Civil Code of the State
of California or any successor statute, including the execution of any
appropriate documents if necessary; provided, however, Landlord may itself
execute and file the same on behalf of Tenant as Tenant's agent for such
purpose.

                                    SECTION 6

                     COMPLETION OF THE TENANT IMPROVEMENTS;
                             LEASE COMMENCEMENT DATE

      Except as provided in this Section 6, the Lease Commencement Date shall
occur as set forth in the Summary of this Lease. For purposes of this Lease
"Substantial Completion" of the Tenant Improvements shall occur upon the
completion of construction of the Tenant Improvements in the Premises pursuant
to the Construction Drawings, with the exception of any punch list items and any
Tenant fixtures, work-stations, built-in furniture, or equipment to be installed
by Tenant or under the supervision of a contractor. To the extent there is a
delay or there are delays in the Substantial Completion of the Tenant
Improvements or in the occurrence of any of the other conditions precedent to
the Lease Commencement Date as set forth in the Summary of this Lease as a
result of the following:

      6.1 Tenant's failure to furnish or approve any item required to be
furnished or approved by Tenant within the time periods provided for in this
Work Letter;

      6.2 A material breach by Tenant of the terms of this Work Letter or this
Lease;

      6.3 Tenant's request for changes in any of the Construction Drawings;

      6.4 Tenant's requirement for materials, components, finishes or
improvements which are not available in a commercially reasonable time or which
are different than Landlord's standard improvement package items for the
Building;

      6.5 Changes to the Base, Shell and Core required by the Construction
Drawings; or

      6.6 Any other acts or omissions of Tenant, or its agents, or employees;

then, notwithstanding anything to the contrary set forth in this Lease or this
Work Letter and regardless of the actual date of the Substantial Completion of
the Tenant Improvements, the Lease Commencement Date shall be deemed to be the
date the Lease Commencement Date would have occurred pursuant to the Summary if
no Tenant delay or delays, as set forth above, had occurred. No Tenant Delay
shall be deemed to occur unless and until Landlord has provided written notice
to Tenant specifying the event or circumstance causing the delay. The period of
the Tenant Delay shall not be deemed to commence for any purpose under this
Section 6 until twenty-four (24) hours after Tenant's receipt of written notice
from Landlord specifying the facts and circumstances resulting in the delay.


                               EXHIBIT C - PAGE 4
<PAGE>

                                    SECTION 7

                                  MISCELLANEOUS

      7.1 Tenant's Entry Into the Premises Prior to Substantial Completion.
Provided that Tenant and its agents do not interfere with Contractor's work in
the Project, Building and the Premises, Landlord shall allow Tenant access to
the Premises prior to the Substantial Completion of the Tenant Improvements for
the purpose of Tenant installing over-standard equipment or fixtures (including
Tenant's data and telephone equipment, wall and floor coverings, security
systems and millwork) in the Premises. Tenant shall hold Landlord harmless from
and indemnify, protect and defend Landlord against any loss or damage to the
Project, Building or Premises and against injury to any persons caused by
Tenant's actions pursuant to this Section 7.1.

      7.2 Freight Elevators. Landlord shall, consistent with its obligations to
other tenants of the Building, and subject to the needs of Landlord with respect
to Landlord's construction work in the Building, make the freight elevator (if
any) reasonably available to Tenant in connection with initial decorating,
furnishing and moving into the Premises.

      7.3 Tenant's Representative. Tenant has designated Steve Tripp as its sole
representative with respect to the matters set forth in this Work Letter, who,
until further notice to Landlord, shall have full authority and responsibility
to act on behalf of the Tenant as required in this Work Letter.

      7.4 Landlord's Representative. Landlord has designated Michael D. Barker
as its sole representative with respect to the matters set forth in this Work
Letter, who, until further notice to Tenant, shall have full authority and
responsibility to act on behalf of the Landlord as required in this Work Letter.

      7.5 Tenant's Agents. At Landlord's option, all subcontractors, laborers,
materialmen, and suppliers retained directly by Tenant shall all be union labor.

      7.6 Calendar Days. Unless otherwise indicated, all references herein to a
"number of days" shall mean and refer to calendar days.

      7.7 Tenant's Lease Default. Notwithstanding any provision to the contrary
contained in this Lease, if an event of default as described in Section 17 of
this Lease, or a default by Tenant under this Work Letter, has occurred at any
time on or before the Substantial Completion of the Tenant Improvements, then
(i) in addition to all other rights and remedies granted to Landlord pursuant to
this Lease, Landlord shall have the right to cause Contractor to cease the
construction of the Premises (in which case, Tenant shall be responsible for any
delay in the Substantial Completion of the Tenant Improvements caused by such
work stoppage as set forth in Section 6 of this Work Letter), and (ii) all other
obligations of Landlord under the terms of this Work Letter shall be forgiven
until such time as such default is cured pursuant to the terms of this Lease.


                               EXHIBIT C - PAGE 5
<PAGE>

                             SCHEDULE 1 TO EXHIBIT C

                                HAMILTON LANDING

                            BASE, SHELL AND CORE WORK

                                HAMILTON LANDING

                            BASE, SHELL AND CORE WORK

<TABLE>
<S>                                                                   <C>
Summary of work provided by Landlord as part of                       Summary of work to be constructed as part of Tenant
Base, Shell and Core Work as set forth in the base                    Improvements and paid from Allowance.
Building construction documents


1.  EXTERIOR ENCLOSURE:                                               1.  EXTERIOR ENCLOSURE:

Complete construction to provide a weatherproof                       Additional doors, skylights, or revisions to Core and
enclosure including roof, exterior walls, exterior                    Shell Standards and Specifications.
doors and windows (some operable). Insulation
provided as required to meet California Energy Code                   All Tenant required exterior enclosure items to be
                                                                      by same manufacturer and of same quality, finish,
Exterior enclosure to include new painted window                      color, etc. as standard established in Core and Shell
wall, entry and exit doors, new roof, repaired and                    Specifications.
repainted exterior walls, new gutters and drains,
mechanical louvers, curbs and waterproofing


2.  ACCESS FLOORING SYSTEM AND HVAC DISTRIBUTION:                     2.  ACCESS FLOORING SYSTEM AND HVAC DISTRIBUTION:

Existing ground floor slab to be cleaned and sealed,                  Cutting, additional support or other revision to
column footings, columns and raised mechanical                        Access Floor as required for special Tenant
pressurized access floor system installed above slab                  partitions, Tenant designed structures with the space,
providing for HVAC distribution and grills/louvers in                 FF&E, mechanical, electrical, plumbing or
standard configuration.  Floor diffusers are provided                 technology distribution, floor finishes, or other
at one diffuser per 100 sq. ft. of floor space.                       Tenant related items.

Access Floor/HVAC Distribution including                              Floor air diffusers, controls, plenum stops, volume
grilles/louvers under Access Floor system.  This                      dampers or other equipment devices or special
work covers the Main Group, secondary HVAC                            construction in addition to the quantity supplied as
distribution, air volume boxes with reheat and HVAC                   part of Core & Shell and additional HVAC controls
control for the premises (excluding special zone                      due to Tenant space configuration.
control requirements).   Floor finish is standard
cementicious access floor as specified in                             Floor finishes: Carpet Tile, Vinyl Tile or other
Construction Documents.                                               approved finish. Tenant selected finishes to allow
                                                                      Access Floor to be accessible as required to maintain
                                                                      building systems.


3.  MEZZANINE/LEVEL TWO:                                              3.  MEZZANINE/LEVEL TWO:

Columns, beams, joists and decking for selected area                  Modifications to mezzanine plan as approved by
of mezzanine to comply with one of the Mezzanine                      Landlord including any additional engineering
Plan Options. Mezzanine floor loads to be designed                    required by Tenant to accommodate special loads or
to 50 lbs./square foot plus code required partition                   configurations, modifications to guardrails or
loads. Forty-two (42) inch high wall including                        mechanical distribution necessitated due to special
</TABLE>


                        SCHEDULE 1 TO EXHIBIT C - PAGE 1
<PAGE>

<TABLE>
<S>                                                                   <C>
drywall on Atrium side with a painted cap.                            configuration of Tenant Improvements or loads in
                                                                      excess of the specified performance of the Access
                                                                      Floor.

                                                                      Dropped ceilings and or other ceiling elements or
                                                                      acoustic elements as desired underside of Mezzanine
                                                                      and in closed offices.


4.  ROOF STRUCTURE:                                                   4.  ROOF STRUCTURE:

Underside of upper roof structure trusses and other                   Any painting of Underside of Mezzanine, subject to
miscellaneous steel members which are part of the                     Tenant design requirements, shall be part of the
base building in the vault area will be painted                       Tenant Improvement work.
Building Standard white.

                                                                      All anchors to or elements suspended from roof or
                                                                      mezzanine structure to be engineered by Tenant
                                                                      engineer and approved by Landlord.

                                                                      Reinforcing to Core and Shell structure resulting
                                                                      from Tenant Improvements plan to be designed and
                                                                      provided by Tenant.


5.  PERIMETER WALLS:                                                  5.  PERIMETER WALLS:

Interior surfaces of interior walls will be clean. Steel              5/8" drywall finish including painting and/or any
studs and insulation will be applied as required to                   other approved finish to be applied over drywall or
meet energy code. System will be coordinated with                     concrete. Base as required by Tenant partition plan.
window and doorframes to align with any required
Tenant application of 5/8" drywall finish.


6.  COMMON ROOMS (TOILET ROOMS, MULTI TENANT                          6.  COMMON ROOMS (TOILET ROOMS, MULTI TENANT
CORRIDOR (IF REQ'D.), JANITOR CLOSET, ELECTRICAL CLOSET,              CORRIDOR (IF REQ'D.), JANITOR CLOSET, ELECTRICAL CLOSET,
TECHNOLOGY CLOSET, MECHANICAL ROOMS):                                 TECHNOLOGY CLOSET, MECHANICAL ROOMS):

Walls and ceilings where applicable, will be steel                    All finishes on Tenant side of common room walls
stud/drywall partitions or CMU partitions as                          including painting or any other approved finish.
determined by Landlord.  All walls will be entirely                   Building Standard vinyl base as required on Tenant
finished on interior (room side) of rooms including                   side of walls.
tile, paint or other appropriate finish and will extend
through access floor as required.  Acoustic materials                 Additional doors, controlled access, expansion of or
will be included as deemed appropriate by Landlord.                   relocation of common rooms including demolition of
Painted backboards will be included in technology                     existing and all necessary extensions of utilities and
rooms.  Tenant side of walls will be fire-taped                       all engineering required to support revisions as
drywall or unfinished CMU.                                            approved by Landlord.  Additional rooms for
                                                                      purposes similar to common rooms in addition to
                                                                      Core and Shell rooms.


7.  ELEVATOR:                                                         7.  ELEVATOR:

One elevator installed and operational with all call                  Upgrades to Core and Shell as requested by Tenant
buttons and hall lanterns. Interior to be                             including additional elevators, special upgrades to
manufacturer's standard finishes as selected by                       cab finishes or selected operation, hall lanterns, call
Landlord.                                                             buttons, door and frame finishes.
</TABLE>


                        SCHEDULE 1 TO EXHIBIT C - PAGE 2
<PAGE>

<TABLE>
<S>                                                                   <C>
8.  STAIRS:                                                           8.  STAIRS:

Exterior exit stairs with access door as required to                  Upgrades to exterior exit stairs as requested by
meet mezzanine at full occupancy office load (100                     Tenant including expansion of stair width (to the
sq. ft./person).  Stair to be painted steel.                          extent allowed by code) to meet additional exit
                                                                      requirements or potential addition of bridge element
Interior stair to be provided as non-exit stair adjacent              for multi building occupancy.
to elevator, painted steel with painted steel handrail
and guardrail.                                                        Upgrades to interior stair as requested by Tenant
                                                                      including relocation or redesign, revisions to finishes,
                                                                      handrail or guardrail, or any other adjustments to
                                                                      Core and Shell including all required engineering.


9.  FIRE SUPPRESSION:                                                 9.  FIRE SUPPRESSION:

Wet sprinkler system including all supply and                         Reconfiguration of the sprinkler system heads or
distribution for standard distribution of 225 sq.                     added sprinkler heads to accommodate Tenant space
ft./head outside of common rooms.  Common rooms                       layout.
complete as required to meet building code.
                                                                      Extension of dropped heads to Tenant ceiling height
                                                                      may result in added Tenant improvement cost.

                                                                      All additional heads required due to Tenant layout to
                                                                      comply with building code including secondary
                                                                      heads in rooms with dropped ceilings. Dry pipe
                                                                      sprinkler system or other special fire suppression
                                                                      required due to special Tenant need including any
                                                                      special HVAC system or alarm system required to
                                                                      meet building code.


10.  MECHANICAL SYSTEM:                                               10.  MECHANICAL SYSTEM:

HVAC as required to produce indoor conditions as                      Any HVAC distribution or special zone controls
noted below based on outdoor conditions stated:                       required by Tenant in addition to the pressurized
                                                                      access floor system as described in 2.C.
                     Outdoor              Indoor
                                                                      Distribution from condenser water loop cooling
Summer                                                                tower for additional condenser water required by any
dry bulb             87(Degree)           75(Degree)                  special Tenant provided equipment including
                                                                      additional HVAC for 24 hour or overtime cooling or
Winter                                                                special computer equipment cooling requirements.
dry bulb             33(Degree)           72(Degree)

Mechanical system is a condenser water system with
direct exchange air units located in the building
towers. Conditioned air is supplied to Tenant spaces
through a pressurized under floor system.

HVAC for all Common Rooms provided by Landlord.


11.  LIFE SAFETY SYSTEM:                                              11.  LIFE SAFETY SYSTEM:
     ------------------                                                    ------------------
</TABLE>


                        SCHEDULE 1 TO EXHIBIT C - PAGE 3
<PAGE>

<TABLE>
<S>                                                                   <C>
As provided in the Base Building Construction                         Upgrades to the Base Building System as required by
Drawings.                                                             special Tenant layout.


12.  WINDOW BLINDS:                                                   12.  WINDOW BLINDS:

Horizontal mini blinds provided on all exterior                       Any upgrades to building standard such as blackout
windows. Cost of window blinds charged against the                    shades or other draperies to be installed to interior of
Allowance shall be $0.56 per square foot of usable                    windows in addition to Building Standard horizontal
area in the Premises.                                                 mini blinds.

Type and Color: To be selected by Landlord.


13.  PARTITION/DRYWALL SYSTEMS:                                       13.  PARTITION/DRYWALL SYSTEMS:

N/A except within building common areas.                              5/8" drywall on each side of steel studs minimum
                                                                      spacing 24"oc of size, gauge and spacing to resist
                                                                      5 per sq. ft. at l/120. Stud size to be maintained as
                                                                      consistent as possible. Tenant partitions to extend
                                                                      from access floor to ceiling for common partitions.
                                                                      Tenant Demising partitions to extend from access
                                                                      floor to underside of Mezzanine (Level 2) structure
                                                                      on level one or to underside of roof-vault or other as
                                                                      acceptable to Landlord on the second level for
                                                                      demising partitions. All surfaces to be taped and
                                                                      floated smooth (level 4 finish) with base.

                                                                      Cost of demising partitions to be split 50% to each
                                                                      tenant when demising partition is a common wall
                                                                      between two tenants.

                                                                      If secondary ceiling in second floor rooms as
                                                                      required by Tenant ceiling is to be per Building
                                                                      Standard materials or as approved by Landlord.


14.  CEILING SYSTEM:                                                  14.  CEILING SYSTEMS:

Dropped ceilings and or 2' x 2' lay in Donn Fineline                  Truss system above Mezzanine (Level 2) and open
tile ceiling grid system or drywall ceiling where                     atrium area is to remain open without dropped ceiling
appropriate provided in common rooms and building                     system. Tenant may elect to install a drop ceiling per
lobby only.                                                           building standard as desired at underside of
                                                                      Mezzanine (Level 2) or in closed rooms. At north
                                                                      south exterior walls any Tenant installed ceilings are to
                                                                      terminate at drywall facia.


15.  DOORS & HARDWARE:                                                15.  DOORS & HARDWARE:

Solid Core, 3" x 8'6", paint grade veneer, pre-finished               All Tenant doors within Tenant's leased premises in
doors in white painted aluminum 11/2" frames or                       addition to Core and Shell and any approved special
painted hollow metal frames.  Hardware to be                          revisions to Core and Shell doors which are provided
Schlage L Series brushed chrome or Stainless with 3                   by Landlord.
butts per door.  Doors and hardware provided for all
common rooms and code required entrances/exits
into Tenant spaces.
</TABLE>


                        SCHEDULE 1 TO EXHIBIT C - PAGE 4
<PAGE>

<TABLE>
<S>                                                                   <C>
16.  PAINTING:                                                        16.  PAINTING:

Interior of all Common Rooms will receive two coats                   Tenant side of all Common Rooms, demising
eggshell latex enamel wall paint. Metal portions of                   partitions, perimeter walls and all new Tenant
window wall will be painted.                                          surfaces to receive a primer coat and two (2) coats of
                                                                      Building Standard paint.


17.  ELECTRICAL SERVICE:                                              17.  ELECTRICAL SERVICE:

Base Building Electrical Panel provide in each of two                 Tenant electrical panels required by Tenant in excess
electrical rooms.                                                     of base building main electrical panel.  To be located
                                                                      by Tenant in leased Premises.
All base building electrical power services up to a 2
watts per square feet capacity will be provided from                  Tenant's furniture systems may be electrified from
the access floor system in a standard power grid                      under building standard floor power grid.  Power
configuration.  Landlord shall provide conduit box                    distribution, wire floor box wiring, whips, etc., for
layout only.  Landlord shall provide empty preset                     Tenant's power needs to be installed in preset boxes.
floor boxes to accommodate Tenant's power and
telecom/data at one box per 200 square feet of NRA.                   Special electrical outlets over the standard service
Shell and Core includes 3 watts per square feet in                    may be specified by Tenant at Tenant's additional
additional capacity for Tenant lighting.                              cost.

                                                                      All lighting controls such as dimmers or additional
                                                                      controls may be specified by Tenant at Tenant's
                                                                      additional cost.

                                                                      Color of plates to be approved by Landlord.


18.  LIGHTING FIXTURES:                                               18.  LIGHTING FIXTURES:

Uplighting for all areas of underside of roof truss, to               Direct lighting per Building Standard at underside of
provide indirect lighting to the Mezzanine level and                  truss as desired to provide Tenant with special or
Atrium floor area to a level of 35 foot-candles.                      supplemental additional light level requirements.

2' x 4' cell parabolic fluorescent lay in fixtures in                 All direct or indirect lighting on underside of
common rooms or strip lights as required by code for                  Mezzanine to provide lighting in first floor occupied
mechanical rooms.                                                     spaces.

                                                                      Building standard lights in all Tenant spaces
                                                                      requiring additional special lighting in addition to
                                                                      standard roof truss uplighting may be selected by
                                                                      Tenant.


19.  FLOOR COVERINGS:                                                 19.  FLOOR COVERING:

Landlord to provide carpet in common areas and                        Floor coverings to be compatible with Access Floor
special floor finishes in the Building Lobby.                         system and shall be specified by Tenant's architect to
                                                                      cover all Access Floor areas.  Standards established
Ceramic Tile:  2x2 unglazed tile where specified in                   by the Landlord are for floor coverings include the
restrooms.  All access floor to remain accessible or as               following options:
otherwise approved by Landlord.
                                                                      Carpet:  3' x 3' carpet tiles or roll carpet.
</TABLE>


                        SCHEDULE 1 TO EXHIBIT C - PAGE 5
<PAGE>

<TABLE>
<S>                                                                   <C>
                                                                      Resilient Vinyl Flooring:  Tile on Access Floor

                                                                      Color and pattern of carpet, vinyl floor tiles or any
                                                                      ceramic tile within Tenant's premises, may be
                                                                      selected by Tenant, subject to conformance with
                                                                      Building standards and full coverage of the Access
                                                                      Floor areas.
</TABLE>


                        SCHEDULE 1 TO EXHIBIT C - PAGE 6
<PAGE>

                                    EXHIBIT D

                                HAMILTON LANDING

                                 TENANT'S PLANS


                               EXHIBIT D - PAGE 1
<PAGE>

                                    EXHIBIT E

                                HAMILTON LANDING

                           NOTICE OF LEASE TERM DATES

Re:   Office Lease dated ______________, 2002, between Hamilton Marin, LLC, a
      California limited liability company, Landlord, and SPATIALIGHT, INC., a
      New York corporation, Tenant, concerning Suite 100, located at 5 Hangar
      Avenue, Novato, California 94949.

      In accordance with the subject Lease, this Notice will confirm the
      following:

1.    The Premises have been accepted by Tenant as being substantially complete
      in accordance with the Lease and there is no deficiency in construction.

2.    Tenant has possession of the Premises and acknowledges that under the
      provisions of the Lease, the term of said Lease commenced as of
      _______________ for a term of ________ ending on ___________.

3.    In accordance with the Lease, Rent commenced to accrue on
      _________________________.

4.    If the commencement date of the Lease is other than the first day of the
      month, the first billing will contain a pro rata adjustment. Each billing
      thereafter shall be for the full amount of the monthly installment as
      provided for in the Lease.

5.    Rent is due and payable in advance on the first day of each and every
      month. Rent checks should be made payable to Hamilton Marin, LLC and
      delivered to:

                 c/o Barker Pacific Group, Inc.
                 Three Hamilton Landing, Suite 200
                 Novato, California  94949

6.    The number of square feet of Rentable Area in the Premises is __________.

7.    Tenant's Percentage Share is _________%.

Landlord:                                    Tenant:

HAMILTON MARIN, LLC,                         SPATIALIGHT, INC., a New York
a California limited liability company       corporation

By:   Barker Pacific Group, Inc.,
      a Delaware corporation,                By:
      Its Authorized Signatory                  --------------------------------

      By:                                    Print Name:
         -----------------------------                  ------------------------
          Michael D. Barker
          Its Managing Director              Its:
                                                 -------------------------------


                               EXHIBIT E - PAGE 1
<PAGE>

                                    EXHIBIT F

                                HAMILTON LANDING

                              RULES AND REGULATIONS

      Tenant shall faithfully observe and comply with the following Rules and
Regulations. Landlord shall not be responsible to Tenant for the non-performance
of any of said Rules and Regulations by or otherwise with respect to the acts or
omissions of any other tenants or occupants of the Project.

      1. Tenant shall not alter any lock or install any new or additional locks
or bolts on any doors or windows of the Premises without obtaining Landlord's
prior written consent. Tenant shall bear the cost of any lock changes or repairs
required by Tenant. Two keys will be furnished by Landlord for the Premises, and
any additional keys required by Tenant must be obtained from Landlord at a
reasonable cost to be established by Landlord.

      2. All doors opening to public corridors shall be kept closed at all times
except for normal ingress and egress to the Premises, unless electrical
hold-backs have been installed.

      3. Landlord reserves the right to close and keep locked all entrance and
exit doors of the office building during such hours as are customary for
comparable buildings in the vicinity of the Project. Tenant, its employees and
agents must be sure that the doors to the office building are securely closed
and locked when leaving the Premises if it is after the normal hours of business
for the Project. Any Tenant, its employees, agents or any other persons entering
or leaving the Project at any time when it is so locked, or any time when it is
considered to be after normal business hours for the Project, may be required to
sign the security register when so doing. Access to the Project may be refused
unless the person seeking access has proper identification or has made a
previous arrangement with regard to the admission to or exclusion from the
Project of any person. In case of invasion, mob, riot, public excitement, or
other commotion, Landlord reserves the right to prevent access to the Project
during the continuance of same by any means it deems appropriate for the safety
and protection of life and property.

      4. Landlord shall have the right to prescribe the weight, size and
position of all safes and other heavy property brought into the Project. Safes
and other heavy objects shall, if considered necessary by Landlord, stand on
supports of such thickness as is necessary to properly distribute the weight.
Landlord shall not be responsible for loss of or damage to any such safe or
property in any case. All damage done to any part of the Project, its contents,
occupants or visitors by moving or maintaining any such safe or other property
shall be the sole responsibility of Tenant and any expense of said damage or
injury shall be borne by Tenant.

      5. No furniture, freight, packages, supplies, equipment or merchandise
will be brought into or removed from the Building or carried up or down in the
elevators, except upon prior notice to Landlord, and in such manner, in such
specific elevator, and between such hours as shall be designated by Landlord.
Tenant shall provide Landlord with not less than 24 hours' prior notice of the
need to utilize an elevator for any such purpose, so as to provide Landlord with
a reasonable period to schedule such use and to install such padding or take
such other actions or prescribe such procedures as are appropriate to protect
against damage to the elevators or other parts of the Building. In no event
shall Tenant's use of the elevators for any such purpose be permitted during the
hours of 7:00 a.m. - 9:00 a.m., 11:30 a.m. - 1:30 p.m. and 4:30 p.m. - 6:30 p.m.

      6. Landlord shall have the right to control and operate the public
portions of the Project, the public facilities, the heating and air
conditioning, and any other facilities furnished for the common use of tenants,
in such manner as is customary for comparable buildings in the vicinity of the
Project.

      7. The requirements of Tenant will be attended to only upon application at
the Office of the Project or at such office location designated by Landlord.
Tenant shall not request employees of Landlord to perform any work or do
anything outside of their regular duties unless Tenant has received special
instructions from Landlord.

      8. Tenant shall not disturb, solicit, or canvass any occupant of the
Project and shall cooperate with Landlord or Landlord's agents to prevent same.


                               EXHIBIT F - PAGE 1
<PAGE>

      9. The toilet rooms, urinals, wash bowls and other apparatus shall not be
used for any purpose other than that for which they were constructed, and no
foreign substance of any kind whatsoever shall be thrown therein. The expense of
any breakage, stoppage or damage resulting from the violation of this rule shall
be borne by the Tenant who, or whose employees or agents, shall have caused it.

      10. Tenant shall not overload the floor of the Premises, nor mark, drive
nails or screws, or drill into the partitions, woodwork or plaster or in any way
deface the Premises or any part thereof without Landlord's consent first had and
obtained, which consent shall not be unreasonably withheld; provided, however,
that Tenant may, without Landlord's prior consent, place pictures and normal
wall hangings on the Premises so long as Tenant repairs any damage resulting
therefrom and Tenant restores the Premises to its condition prior to the
placement of such items.

      11. Except for vending machines rented for the sole use of Tenant's
employees and invitees and any machines in the Clean Room, no vending machine or
machines of any description other than fractional horsepower office machines,
shall be installed, maintained or operated upon the Premises without the written
consent of Landlord, which shall not unreasonably be withheld.

      12. Tenant shall not use or keep in or on the Premises or the Project any
kerosene, gasoline or other inflammable or combustible fluid, except for
Permitted Hazardous Substances.

      13. Tenant shall not use any method of heating or air conditioning other
than that which may be supplied by Landlord, without the prior written consent
of Landlord.

      14. Tenant shall not use, keep or permit to be used or kept, any foul or
noxious gas or substance in or on the Premises, or permit or allow the Premises
to be occupied or used in a manner offensive or objectionable to Landlord or
other occupants of the Project by reason of noise, odors, or vibrations, or
interfere in any way with other tenants or those having business therein.

      15. Tenant shall not bring into or keep within the Project or the Premises
any birds, bicycles or other vehicles. Dogs may be brought to the Project
subject to compliance with the "Dog Policy" summarized in Exhibit F-1.

      16. No cooking shall be done or permitted by any Tenant on the Premises,
nor shall the Premises be used for the storage of merchandise, for lodging or
for any improper, objectionable or immoral purposes. Notwithstanding the
foregoing, Underwriters' laboratory-approved equipment and microwave ovens may
be used in the Premises for heating food and brewing coffee, tea, hot chocolate
and similar beverages, provided that such use is in accordance with all
applicable federal, state and city laws, codes, ordinances, rules and
regulations, and does not cause odors which are objectionable to Landlord and
other tenants.

      17. Landlord will approve where and how telephone and other
telecommunication wires are to be introduced to the Premises. No boring or
cutting for wires shall be allowed without the consent of Landlord. The location
of telephone, call boxes and other office equipment affixed to the Premises
shall be subject to the approval of Landlord.

      18. Landlord reserves the right to exclude or expel from the Project any
person who, in the judgment of Landlord, is intoxicated or under the influence
of liquor or drugs, or who shall in any manner do any act in violation of any of
these Rules and Regulations.

      19. Tenant, its employees and agents shall not loiter in the entrances or
corridors, nor in any way obstruct the sidewalks, lobby, halls, stairways or
elevators, and shall use the same only as a means of ingress and egress for the
Premises.

      20. Tenant shall not waste electricity, water or air conditioning and
agrees to cooperate fully with Landlord to ensure the most effective operation
of the Project's heating and air conditioning system, and shall refrain


                               EXHIBIT F - PAGE 2
<PAGE>

from attempting to adjust any controls. This includes the closing of exterior
blinds, disallowing the sun rays to shine directly into areas adjacent to
exterior windows.

      21. Tenant shall store all its trash and garbage within the interior of
the Premises. No material shall be placed in the trash boxes or receptacles if
such material is of such nature that it may not be disposed of in the ordinary
and customary manner of removing and disposing of trash and garbage in Marin
County without violation of any law or ordinance governing such disposal. All
trash, garbage and refuse disposal shall be made only through entry-ways and
elevators provided for such purposes at such times as Landlord shall designate.

      22. Tenant shall comply with all safety, fire protection and evacuation
procedures and regulations established by Landlord or any governmental agency.

      23. Tenant shall assume any and all responsibility for protecting the
Premises from robbery and pilferage, which includes keeping doors locked and
other means of entry to the Premises closed when the Premises are not occupied.

      24. Landlord may waive any one or more of these Rules and Regulations for
the benefit of any particular tenant or tenants, but no such waiver by Landlord
shall be construed as a waiver of such Rules and Regulations in favor of any
other tenant or tenants, nor prevent Landlord from thereafter enforcing any such
Rules or Regulations against any or all tenants of the Building.

      25. No awnings or other projection shall be attached to the outside walls
of the Project without the prior written consent of Landlord. No curtains,
blinds, shades or screens shall be attached to or hung in, or used in connection
with, any window or door of the Premises without the prior written consent of
Landlord. All electrical ceiling fixtures hung in offices or spaces along the
perimeter of the Project must be fluorescent and/or of a quality, tape, design
and bulb color approved by Landlord.

      26. The sashes, sash doors, skylights, windows, and doors that reflect or
admit light and air into the halls, passageways or other public places in the
Building shall not be covered or obstructed by Tenant, nor shall any bottles,
parcels or other articles be placed on the window sills.

      27. The washing and/or detailing of, or the installation of windshields,
radios, telephones in or general work on automobiles shall not be allowed in the
Project.

      28. Food vendors shall be allowed in the Building upon receipt of a
written request from the Tenant. Food vendor shall service only those tenants
which have a written request on file in the Building Management Office. Under no
circumstance shall the food vendor display their products in the public or
common area of the Building, including corridors and elevator lobbies. Any
failure to comply with this rule shall result in immediate, permanent withdrawal
of the vendor from the Project.

      29. Tenants must comply with requests made by the Landlord relative to
informing Tenant's employees of any items of importance affecting them as so
deemed by the Landlord.

      30. Tenant shall comply with any non-smoking ordinance adopted by any
applicable governmental authority.

      31. Landlord reserves the right at any time to change or rescind any one
or more of these Rules and Regulations, or to make such other and further
reasonable Rules and Regulations as in Landlord's judgment may, from time to
time, be necessary for the management, safety, care and cleanliness of the
Premises and Building, and for the preservation of good order therein, as well
as for the convenience of other occupants and tenants. Landlord shall not be
responsible to Tenant or to any other person for the non-observance of said
Rules and Regulations by another Tenant or other person. Tenant shall be deemed
to have read these Rules and Regulations and to have agreed to abide by them as
a condition of its occupancy of the Premises.


                               EXHIBIT F - PAGE 3
<PAGE>

      32. Tenant shall not leave windows open when it rains, and shall be liable
to Landlord and other lessees for any damages to the Building or property of
other Tenants resulting from rain coming into the Building through open windows.
Tenant shall see that the windows and doors of the Premises are closed and
securely locked before leaving the Building. In addition to the waiver of any of
the Landlord's liability in Section 9 of the lease, it is further specifically
provided that Landlord is not liable for any damage resulting to Tenant's
property as the result of windows being left open.

      33. All deliveries to Tenant shall be made at and through the designated
delivery entrance and nowhere else and Tenant shall advise all parties intending
to make deliveries to Tenant of this Rule.

      34. Landlord shall not be responsible to Tenant or to any other person for
the nonobservance or violation of these rules and regulations by any other
Tenant or other person. Tenant shall be deemed to have read these rules and to
have agreed to abide by them as a condition to its occupancy. Landlord shall use
commercially reasonable efforts to cause observance of these rules and
regulations by all Tenants of the Building.


                               EXHIBIT F - PAGE 4
<PAGE>

                                   EXHIBIT F-1

                                   DOG POLICY

The ability to bring a dog to Hamilton Landing is a privilege. A dog owner is
expected to respect the needs and desires of the building owner, other
employees, visitors and tenants concerning having a dog in the office.

The dog owner is expected to follow the guidelines below:

      1.    The dog must be under control of its owner or on a leash when inside
            the leased premises.

      2.    The dog must stay with its owner or designated watcher; other
            employees may allow occasional visits.

      3.    Any dog with fleas or ticks may not be brought into the office.

      4.    Owners are responsible to have dogs completely up to date on all
            immunizations, including rabies, distemper, hepatitis,
            para-influenza, parvo and bordatella.

      5.    Owners should find suitable spots off the building site for
            relieving their dog during walks. The owner is responsible for clean
            up of solid waste.

      6.    If a dog has an accident inside Hamilton Landing Building, the dog
            owner is responsible for clean up. After 2 accidents, the dog will
            not be allowed inside the building until the owner can show that the
            dog has been through some kind of training program.

      7.    Aggressive behavior, loud or repetitive barking, eating human food,
            or other disruptive behavior or persistent odor is unacceptable.

      8.    If any employee has a problem with the dog, he/she should discuss it
            directly with the dog's owner.


                               EXHIBIT F - PAGE 5
<PAGE>

                                    EXHIBIT G

                                HAMILTON LANDING

                      FORM OF TENANT'S ESTOPPEL CERTIFICATE

                           TENANT ESTOPPEL CERTIFICATE

                                  (__________)

---------------------------------------
---------------------------------------
---------------------------------------
---------------------------------------

      THIS IS TO CERTIFY THAT:

      1. The undersigned is the "Tenant" under that certain Office Lease as
amended by that certain ___________________ dated _______________ (collectively,
the "Lease"), between the undersigned and Hamilton Marin, LLC, a California
limited liability company, as the "Landlord" under said Lease. (The premises
covered by and described in the Lease are hereinafter referred to as the
"PREMISES".)

      2. The Lease is in full force and effect and has not been amended or
modified; and there are no documents or written agreements between Tenant and
Landlord with respect to the Lease.

      3. Tenant's interest under the Lease has not been assigned or transferred,
whether for purposes of security or otherwise, and Tenant has not received
notice of any assignment, hypothecation, mortgage or pledge of Landlord's
interest in the Lease or the rents or other amounts payable thereunder.

      4. Tenant has not prepaid any rent under the Lease more than one (1) month
in advance.

      5. No uncured event of default or breach on the part of Landlord has
occurred under the Lease, no event has occurred which gives Tenant the right to
terminate the Lease (or if any such right has arisen, Tenant has waived such
termination right), and Tenant has no defense as to its obligations under the
Lease and claims no setoff or counterclaim against Landlord.

      6. Tenant is not in default in the performance of the terms, covenants and
conditions of the Lease required to be performed on the part of Tenant.

      7. That all conditions to the effectiveness of the Lease have been
satisfied or waived by Tenant.

      8. The person executing this Tenant Estoppel Certificate on behalf of
Tenant is duly authorized to do so.


                               EXHIBIT G - PAGE 1
<PAGE>

      Tenant acknowledges that the addressee of this Certificate and Landlord
shall be entitled to rely upon this certification by Tenant.

Dated:  _________ ___, 200___.

TENANT:                            SPATIALIGHT, INC., a New York corporation


                                   By:
                                                  --------------------------
                                   Print Name:
                                                  --------------------------
                                   Title:
                                                  --------------------------


                               EXHIBIT G - PAGE 2