<PAGE>   1

                                                                   Exhibit 10.31


                                  LEASE BETWEEN


                       BEDFORD WOODS LIMITED PARTNERSHIP I


                                       AND

                               RSA SECURITY, INC.

                                       FOR

   188,220 SQUARE FEET AT BEDFORD WOODS, BUILDING 3 - 174 MIDDLESEX TURNPIKE,

                             BEDFORD, MASSACHUSETTS


                                    I N D E X
                                    ---------

REFERENCE DATA

Section 1.1       Subject Referred To                                        1
Section 1.2       Exhibits                                                   4

ARTICLE II - PREMISES AND TERM:

Section 2.1       Premises                                                   5
Section 2.2       Term                                                       5

ARTICLE III - CONSTRUCTION:

Section 3.1       Initial Construction                                       6
Section 3.1.1     Tenant's Work                                              10
Section 3.1.2     Tenant's Construction Work                                 11
Section 3.2       Preparation of Premises for Occupancy                      12
Section 3.2.1     Partial Occupancy and Rent Commencement                    14
Section 3.3       General Provisions Applicable to Construction              15
Section 3.4       Representatives                                            15
Section 3.5       Force Majeure                                              16
Section 3.6       Arbitration by Architects                                  16
Section 3.7       Warranty of Landlord's Work and Tenant's Work              17
Section 3.8       Tenant's Contribution to Landlord's Work                   17


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ARTICLE IV - RENT:

Section 4.1        Rent                                                    18
Section 4.2        Operating Cost Reimbursement                            18
Section 4.2.1      Landlord's Operating Costs                              18
Section 4.2.2      Real Estate Taxes                                       22
Section 4.2.3      Utilities                                               23
Section 4.3        Payments                                                24

ARTICLE V - LANDLORD'S COVENANTS:

Section 5.1        Landlord's Covenants during the Term                    25
Section 5.1.1      Building Services                                       25
Section 5.1.2      Additional Building Services                            25
Section 5.1.3      Repairs                                                 25
Section 5.1.4      Quiet Enjoyment                                         26
Section 5.1.5      Intentionally Deleted                                   26
Section 5.1.6      Landlord's Insurance                                    26
Section 5.1.7      Landlord's Indemnity                                    26
Section 5.1.8      Hazardous Materials                                     27
Section 5.1.9      Tenant's Costs                                          27
Section 5.1.10     Park Common Areas                                       27
Section 5.2        Interruptions                                           28

ARTICLE VI - TENANT'S COVENANTS:

Section 6.1        Tenant's Covenants during the Term                      29
Section 6.1.1      Tenant's Payments                                       29
Section 6.1.2      Repairs and Yielding Up                                 29
Section 6.1.3      Occupancy and Use                                       29
Section 6.1.4      Rules and Regulations                                   29
Section 6.1.5      Compliance with Laws and Safety Appliances              30
Section 6.1.6      Assignment and Subletting                               30
Section 6.1.7      Indemnity                                               33
Section 6.1.8      Tenant's Liability Insurance                            33
Section 6.1.9      Tenant's Workers' Compensation Insurance                34
Section 6.1.10     Landlord's Right of Entry - Signs and Flags             34
Section 6.1.11     Loading                                                 34
Section 6.1.12     Landlord's Costs                                        34
Section 6.1.13     Tenant's Property                                       35
Section 6.1.14     Labor or Materialmen's Liens                            35
Section 6.1.15     Changes or Additions                                    35
Section 6.1.16     Holdover                                                36
Section 6.1.17     Hazardous Materials                                     37
Section 6.1.18     Signs                                                   38


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Section 6.1.19      Lighting Restrictions                                   39
Section 6.1.20      Transportation Demand Management Plan                   39
Section 6.1.21      Telecommunications and Rooftop Installations            40
Section 6.1.22      Tenant's Authority                                      41
Section 6.1.23      Confidentiality                                         41

ARTICLE VII - CASUALTY AND TAKING:

Section 7.1         Casualty and Taking                                     42
Section 7.2         Reservation of Award                                    45
Section 7.3         Additional Casualty Provisions                          45

ARTICLE VIII - RIGHTS OF MORTGAGEE:

Section 8.1         Priority of Lease                                       46
Section 8.2         Limitation on Mortgagee's Liability                     46
Section 8.3         Mortgagee's Election                                    47
Section 8.4         No Prepayment or Modification                           47
Section 8.5         No Release or Termination                               47
Section 8.6         Continuing Offer                                        48
Section 8.7         Submittal of Financial Statement                        48

ARTICLE IX - DEFAULT:

Section 9.1         Events of Default by Tenant                             48
Section 9.2         Tenant's Obligations After Termination                  49

ARTICLE X - MISCELLANEOUS:

Section 10.1        Titles                                                  50
Section 10.2        Notice of Lease                                         50
Section 10.3        Notices from One Party to the Other                     50
Section 10.4        Bind and Inure                                          51
Section 10.5        No Surrender                                            51
Section 10.6        No Waiver, etc.                                         51
Section 10.7        No Accord and Satisfaction                              51
Section 10.8        Cumulative Remedies                                     52
Section 10.9        Partial Invalidity                                      52
Section 10.10(a)    Landlord's Right to Cure                                52
Section 10.10(b)    Tenant's Right to Cure                                  52
Section 10.11       Estoppel Certificate                                    53
Section 10.12       Waiver of Subrogation                                   53
Section 10.13       Brokerage                                               53
Section 10.14       Access and Security System                              54
Section 10.15       Entire Agreement                                        54


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Section 10.16       Governing Law                                          54
Section 10.17       Additional Representations                             54
Section 10.18       Parking                                                55
Section 10.19       Right of First Offer                                   55
Section 10.19.1     Affiliates                                             58
Section 10.20       Letter Agreements                                      58



                                       iv

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                   Date of Lease Execution: November 16, 2000


                                 REFERENCE DATA

1.1      SUBJECTS REFERRED TO:

         Each reference in this Lease to any of the following subjects shall
         incorporate the data stated for that subject in this Section 1.1.

         LANDLORD:                     Bedford Woods Limited Partnership I, a
                                       Massachusetts limited partnership

         MANAGING AGENT:               The Gutierrez Company, a Delaware
                                       Corporation

         LANDLORD'S AND MANAGING       Burlington Office Park
         AGENT'S ADDRESS:              One Wall Street
                                       Burlington, Massachusetts 01803

         LANDLORD'S REPRESENTATIVE:    John A. Cataldo

         LANDLORD'S CONSTRUCTION       Arturo J. Gutierrez or John A. Cataldo
         REPRESENTATIVES:

         TENANT:                       RSA Security, Inc., a Delaware
                                       corporation

         TENANT'S ADDRESS              Prior to Term Commencement Date:
         (FOR NOTICE & BILLING):
                                       20 Crosby Drive
                                       Bedford, MA 01730

                                       After Term Commencement Date:
                                       Building 3 - Bedford Woods
                                       174 Middlesex Turnpike
                                       Bedford, Massachusetts 01730

         TENANT'S REPRESENTATIVE(S):   John F. Kennedy

         TENANT'S CONSTRUCTION
         REPRESENTATIVE(S):            Richard White

<PAGE>   6


     BUILDING:                     Four (4) story building consisting of
                                   188,220 rentable square feet constructed
                                   upon the land described on Exhibit A
                                   attached hereto (the "Lot") in
                                   accordance with the final Landlord's
                                   Plans and Tenant's Plans (as defined in
                                   Article III hereof, and any replacements
                                   thereof) and any alterations and
                                   additions thereto, including the
                                   Tenant's Work (as hereinafter defined).

     RENTABLE FLOOR AREA OF        188,220 rentable square feet
     TENANT'S SPACE:

     TOTAL RENTABLE FLOOR AREA     188,220 rentable square feet
     OF THE BUILDING:

     SCHEDULED TENANT'S DESIGN     March 30, 2001, subject to the
     COMPLETION DATE               provisions of Section 3.1

     SCHEDULED TERM                December 2, 2001
     COMMENCEMENT DATE:

     OUTSIDE DELIVERY DATE:        Per Section 3.2

     TERM EXPIRATION DATE:         Fifteen (15) years following the Term
                                   Commencement Date determined in
                                   accordance with Section 3.2 subject to
                                   extension upon the substantial
                                   completion of Building 4 on Lot 4 in the
                                   Park (as hereinafter defined) pursuant
                                   to a lease by and between Tenant and
                                   Landlord dated as of even date herewith
                                   (the "Building 4 Lease") to provide for
                                   a revised Term hereunder of fifteen (15)
                                   Years following the term commencement
                                   date under the Building 4 Lease and
                                   subject to extension in accordance with
                                   Exhibit F.

     TERM:                         Fifteen (15) years, subject to extension
                                   in accordance with Exhibit F.

     FIXED RENT:                   Years 1-3:  $3,318,319/Year; ($17.63/RSF);
                                   $276,526.58/month
                                   Years 4-6:  $3,694,759/Year; ($19.63/RSF);
                                   $307,896.58/month


                                       2

<PAGE>   7


                                       Year 7-10: $4,259,419/Year; ($22.63/RSF);
                                       $354,951.58/month
                                       Years 11-15: $5,012,299/Year;
                                       ($26.63/RSF); $417,691.58/Month

INITIAL ANNUAL ESTIMATED OPERATING
COSTS: (Not Including Real
Estate Taxes)                          $235,275.00/Year; $19,606.25 Month;
                                       ($1.25/RSF)

INITIAL ANNUAL ESTIMATED REAL
ESTATE TAXES                           $367,029.00/Year; $30,585.75/Month;
                                       ($1.95/SF)

SECURITY DEPOSIT:                      Not Applicable

GUARANTOR:                             Not Applicable

PERMITTED USES:                        Research, development, general office,
                                       including training and administrative
                                       purposes, light manufacturing, assembly
                                       and such other uses that are ancillary
                                       and accessory thereto.

REAL ESTATE BROKERS:                   Grubb & Ellis Company
                                       Meredith & Grew, Inc.
PUBLIC LIABILITY INSURANCE:
BODILY INJURY AND PROPERTY DAMAGE:

                                       Each Occurrence:   $1,000,000.00
                                       Aggregate:  $2,000,000.00
                                       Umbrella:   $3,000,000.00

SPECIAL PROVISIONS:                    Option to Extend:       Per Exhibit F
                                       Market Rent:            Per Exhibit P
                                       Right of First Refusal: Per Exhibit Q
                                       Expansion Option:       Per Exhibit R
                                       Right of First Offer:   Per Section 10.19
                                       Letter Agreements:      Per Section 10.20



                                       3

<PAGE>   8


1.2      EXHIBITS

         The Exhibits listed below in this Section are incorporated in this
         Lease by reference and are to be construed as part of this Lease:

         EXHIBIT A      Plans Showing Tenant's Space, the Lot and the Park
                        (including the Building Parking Area and Common Areas)
         EXHIBIT A-1    Legal Description of the Lot
         EXHIBIT B-1    Preliminary Base Building Plans
         EXHIBIT B-2    Base Building Outline Specifications
         EXHIBIT C-1    Form of Certificate of Substantial Completion
         EXHIBIT C-2    Form of Certificate of Final Completion
         EXHIBIT D      Intentionally Deleted
         EXHIBIT E      Rules and Regulations
         EXHIBIT F      Option to Extend
         EXHIBIT G      Tenant Estoppel Certificate
         EXHIBIT H      Tenant's Contractors and Subcontractors Minimum
                        Insurance Requirements
         EXHIBIT I      Park Covenants
         EXHIBIT J      Subordination, Non-Disturbance and Attornment Agreement
         EXHIBIT K      Form of Work Change Order
         EXHIBIT L      Definition of Cost of the Work
         EXHIBIT M      Intentionally Deleted
         EXHIBIT N      Intentionally Deleted
         EXHIBIT O      Letter Agreements
         EXHIBIT P      Definition of Market Rent
         EXHIBIT Q      Right of First Refusal
         EXHIBIT R      Expansion Option
         EXHIBIT S      Schedule
         EXHIBIT T      Form of Notice of Lease


                                       4

<PAGE>   9


                                   ARTICLE II
                                PREMISES AND TERM

2.1      PREMISES

         Subject to and with the benefit of the provisions of this Lease,
Landlord hereby leases to Tenant and Tenant leases from Landlord, the Rentable
Floor Area of Tenant's Space in the Building (hereinafter, the "Tenant's
Space"), together with the appurtenances described below. Tenant's Space as the
same may be expanded pursuant to Exhibit R, with such appurtenances, is
hereinafter collectively referred to as "the Premises".

         Tenant shall have, as appurtenant to the Premises, the right to use in
common with other tenants of the Park, as hereinafter defined, the areas shown
on the Plan attached hereto as part of Exhibit A as "Building Parking Area", all
subject to and as further provided in Section 10.18 hereof.

         Tenant shall also have, as appurtenant to the Premises, the right to
use in common with others entitled thereto, subject to reasonable rules of
general applicability to tenants and owners of other lots in the park, commonly
known and referred to as the Bedford Woods Office Park and shown on the Plan of
the Park attached hereto as part of Exhibit A (the "Park") from time to time
made by Landlord in accordance with Section 6.1.4 of which Tenant is given
written notice: (a) the common areas now or hereafter located at the Park (the
"Common Areas"), including, without limitation, the Common Areas shown on the
Plan of the Park attached hereto as Exhibit A, as such Common Areas may be
amended or modified by Landlord from time to time during the Term hereof
provided however that (i) any amendments or modifications to such Common Area
will not materially adversely effect Tenant's ability to access the Premises
(ii) Landlord will provide Tenant prior written notice thereof and (iii)
provided further that any such amendments or modifications to the Common Areas
are reasonably functionally equivalent to the portion of the Common Areas that
they amend or replace, (b) all rights of ingress and egress to and from the
Building and to and from the Park, all service areas, drainage structures and
areas for surface water runoff, including, without limitation, storm drainage
systems, ground water recharge areas and detention areas, (c) all driveways,
roadways, sidewalks and footways and lighting systems, (d) all parking areas
designated as common or visitors parking areas for use of the entire Park, if
any, (e) all other rights appurtenant to the Lot and the Building, and (f) all
utility lines, electricity, water and sewage disposal pipes and structures.

2.2      TERM

         To have and to hold for a period (the "Term") commencing on the Term
Commencement Date determined in accordance with Section 3.2 (which said date is
at times being hereafter referred to as the "Commencement Date") and continuing
until the Term Expiration Date, unless sooner terminated as provided in
Sections 3.2, 7.1 or in Article IX, or unless extended pursuant to Exhibit F.


                                       5

<PAGE>   10

                                   ARTICLE III
                                  CONSTRUCTION

3.1      INITIAL CONSTRUCTION

         Landlord shall fully construct the base Building in accordance with the
preliminary base building plans, including, without limitation, floor plans,
elevations and site plan(s) (collectively, the "PBBP") and Base Building Outline
Specifications attached hereto as Exhibits B-1 and B-2, respectively (all of
such work being collectively referred to as the "Landlord's Work"). In the event
of differences between the PBBP or the Landlord's Plans (as hereinafter defined)
and the Base Building Outline Specifications, the Base Building Outline
Specifications shall govern and control until the Landlord's Plans (as
hereinafter defined) are prepared.

         A complete set of final base Building plans and construction drawings
and specifications, such drawings and specifications to include a detailed
schedule of core base Building finish items such as, but not limited to,
carpets, doors, hardware, ceiling grids/tiles, lavatory fixtures, light
fixtures, window blinds, lobby allowance and paint (collectively, the
"Landlord's Plans") shall be prepared by Landlord, at its sole cost and expense.
Landlord and Tenant agree to work together with Landlord's architect, Symmes
Maini & McKee Associates, Inc. in order to achieve a design that meets the
standard set forth below. Furthermore, Landlord has delivered, except for
interior details, Landlord's Plans to Tenant entitled "The Gutierrez Company,
Building 3, Bedford Woods, Bedford, MA, Tenant Review A1.1, A1.2, A1.3, A1.4,
A2.1, A3.1" dated November 13, 2000 and Landlord's Site Plans entitled "The
Gutierrez Company, Building 3 Bedford Woods, Bedford, MA, Revised Notice of
Intent dated February 4, 1999 Revised through November 8, 2000 and November 10,
2000 C1.1, C2.1, C2.2, C3.1, C3.2, C4.1, C4.2, C5.1, C5.2, C6.1, C6.2, C6.3 and
C6.4, prepared by Symmes, Maini & McKee Associates and Tenant has approved same.
Landlord agrees to use good faith and diligent efforts to deliver the interior
details of Landlord's Plans to Tenant on or before January 15, 2001. Upon
receipt, Tenant shall have five (5) business days to comment upon the interior
details of Landlord's Plans. Landlord and Tenant shall use reasonable efforts to
reach agreement on the interior details of Landlord's Plans by January 26, 2001.
In reaching agreement, Landlord and Tenant shall each approve portions of the
Landlord's Plans that are in acceptable form and shall note their respective
objections to the portions that are unacceptable to each of them so as to enable
Landlord to start construction and order materials in a timely manner. In the
event that Landlord's Plans conform with the PBBP, but Tenant does not approve
the interior details of Landlord's Plans within five (5) business days of
receipt thereof from Landlord, then the Outside Delivery Date (as hereinafter
defined) shall be extended for a number of days equal to the number of Tenant
Plan Delay Days, as such term is hereinafter defined. The number of Tenant Plan
Delay Days are defined as and shall be calculated by determining the actual
number of days as certified by Landlord and its architect that the Term
Commencement Date was delayed by such Tenant's failure to approve the Landlord's
Plans within the required five (5) business days. Landlord agrees to provide
Tenant with written notice of such determination, such notice to include
reasonable detail describing the cause of the delay and the number of Tenant
Plan Delay Days as certified by Landlord and its architect. In addition to such
notice of such determination, Landlord shall promptly provide Tenant a courtesy


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<PAGE>   11


notice upon Tenant's failure to comply with the dates set forth in this
paragraph. If Tenant and Tenant's Architect (as hereinafter defined) disagree
with the existence or calculation of Tenant Plan Delay Days as determined by
Landlord and its architect, then Tenant shall, within five (5) business days of
receipt of Landlord's notice, notify Landlord of its disagreement, whereupon the
dispute shall be determined pursuant to the arbitration procedures described in
Section 3.6 hereof.

         Landlord and Tenant hereby acknowledge and agree that, except as
otherwise set forth herein, following approval by Landlord and Tenant (which
shall be in writing as hereinafter provided), no amendments, modifications or
changes shall be made to the Landlord's Plans without Tenant's prior written
approval in each instance, which such approval shall not be unreasonably
withheld or delayed; provided, however, no such prior approval of Tenant shall
be required if the proposed amendments, modifications or changes are, in
Landlord's reasonable opinion (i) non-material in nature, (ii) replaced by
substantially equivalent or better items and at all times equal to or better
than that of the building located at (the so-called "GenRad Office
Building") Westford Technology Park, Westford, Massachusetts, and (iii) do not
adversely affect the Premises. Without limiting the foregoing, Landlord shall
exercise reasonable efforts to provide Tenant with prior written notice of all
proposed amendments, modifications or changes to the Landlord's Plans.

         Landlord shall, at Tenant's sole cost and expense, cause its architects
and engineers to design enclosed, heated and cooled bridges between the Building
and the proposed Buildings 2 and 4, and provide Tenant with a budget cost
estimate for such bridges and the required Base Building modifications to
accommodate such bridges. Landlord will, at Tenant's sole cost and expense,
modify its Base Building steel, precast, glazing and foundation design to
accommodate such bridges. Unless otherwise directed by Tenant, such materials as
specified in the modified design will be ordered to accommodate the proposed
bridges. Any additional costs associated with such materials, modifications and
upgrades to the Base Building as previously designed and specified will be paid
by Tenant to Landlord whether or not Tenant elects to have Landlord construct
the bridges. In order to expedite the permitting of the Building, Landlord may
elect to apply for any permits required for the construction of the bridges
after receiving the building permit for the Building. Therefore, completion of
the bridge shall NOT be required of Landlord as a condition of Substantial
Completion of Landlord's Work or Tenant's Work or Punch List Work.
Notwithstanding the foregoing, once construction of the bridge to Building 4 is
authorized by Tenant in writing then Landlord shall proceed with diligence to
design and order the bridge materials, apply for permits for construction of the
bridge and construct and complete same with due diligence and speed. The failure
of the Tenant to pay Landlord the costs and expenses incurred as set forth in
this paragraph within ten (10) days of the billing thereof by Landlord shall be
an event of default under this Lease.

         A complete set of construction plans and specifications for Tenant's
Work (as hereinafter defined) shall be prepared by Tenant's Architect, as
hereinafter defined (collectively, the "Tenant's Plans"). The Tenant's Plans
shall be furnished to Landlord as herein provided. Landlord and Tenant hereby
acknowledge and agree that Tenant has selected Margulies & Associates to be
Tenant's Architect for preparation of Tenant's Plans, and the costs of services
of


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<PAGE>   12


such Tenant's Architect shall be borne solely by Tenant. Tenant's Architect (and
Tenant's Representatives) shall be actively involved in the design decisions and
shall be allowed reasonable access to the Lot and the Premises during
construction to monitor Landlord's compliance with the terms and provisions of
this Lease. Landlord and Tenant hereby further agree that Tenant shall be solely
responsible for coordinating with Tenant's Architect for the timely preparation
of Tenant's Plans in accordance with the terms and provisions of this Section
3.1. Attached as Exhibit S is a schedule (the "Schedule") setting forth the
respective dates by which Landlord and Tenant anticipate that (i) Landlord's
Plans shall have been delivered to and approved by Tenant, (ii) Tenant's Plans
shall have been delivered to and approved by Landlord, and (iii) certain
portions of Landlord's Work and Tenant's Work shall be substantially completed.
The parties agree to cooperate with each other and to exercise reasonable
efforts to complete the tasks described in the Schedule by the respective dates
set forth therein, Landlord and Tenant hereby further agreeing that, unless
otherwise expressly set forth herein, failure to meet any of such dates on the
Schedule shall not constitute a default or a delay of any type hereunder.

         Tenant shall deliver the Tenant's Plans to the Landlord by not later
than the Scheduled Tenant's Design Completion Date, provided, however, that (i)
Tenant furnishes to Landlord by not later than December 10, 2000 any information
in the Tenant Plans that affect the Lobby Plans in the Landlord Plans; and (ii)
Tenant furnishes to Landlord by not later than January 8, 2001 any such
information to be contained in the Tenant's Plans that affects Landlord's Work
which shall include but not be limited to the roof and slab penetrations of the
Building. Tenant shall permit Landlord to review and provide input during the
preparation of Tenant's Plans. Upon receipt, Landlord shall have ten (10)
business days to comment upon the Tenant's Plans. Landlord and Tenant shall use
reasonable efforts to reach agreement on the Tenant's Plans within ten (10) days
of Tenant's receipt of Landlord's comments thereto. In reaching such agreement,
Landlord and Tenant shall each approve portions of Tenant's Plans that are
acceptable and shall note their respective objections to the portions that are
unacceptable to each of them so as to enable Landlord to continue construction
and order materials in a timely manner. In connection with Landlord's review of
the Tenant's Plans, or if Tenant fails to deliver Tenant's Plans (or any
modifications thereto) by the date set forth above, Landlord may require by
prompt written notice to Tenant (i) modifications in Tenant's Plans (i.e. if
Tenant's Plans are not compatible with Landlord's Plans), and/or (ii) an
adjustment in the Outside Delivery Date (such adjustment to be determined by
Landlord in its reasonable judgment). Landlord's notice to Tenant shall include
reasonable detail describing the cause of the adjustment and/or the extent of
the incompatibility with reasonable specificity. Any such extension in time,
whether mutually agreed to by Landlord and Tenant or determined by their
respective architects in the event of dispute pursuant to Section 3.6, shall
result in Tenant's Plan Delay Days as hereinbefore determined. In addition,
Landlord will not approve Tenant's Plans which involve any construction,
alterations or additions requiring unusual expense to readapt the Premises to
normal office use on the Term Expiration Date, unless Tenant first gives
assurances acceptable to Landlord that such readaptation shall be made prior to
such termination without expense to Landlord. All revisions and modifications to
the Tenant's Plans shall be made promptly by Tenant and revised sets of Tenant's
Plans shall be forthwith furnished to Landlord upon Tenant's receipt thereof,
Landlord hereby agreeing to inform Tenant in writing during the plan approval
process and, in any event,


                                       8

<PAGE>   13

prior to the installation thereof, of any such items that may require unusual
expense to readapt the Premises as aforesaid and any items that must be removed
by Tenant at the end of the Term or earlier termination of this Lease. All
revisions and modifications to the Tenant's Plans shall be made promptly by
Tenant and revised sets of Tenant's Plans shall be forthwith furnished to
Landlord upon Tenant's receipt thereof. Landlord and Tenant hereby further agree
to acknowledge in writing when final approval by Landlord and Tenant of Tenant's
Plans (and Landlord's Plans) has occurred.

         Landlord shall have fifteen (15) business days after final approval of
Tenant's Plans and Landlord's receipt of final and complete sets of approved
Tenant's Plans, which such final approval has been acknowledged in writing by
Landlord and Tenant as aforesaid, to price the cost of Tenant's Work (as
hereinafter defined) in accordance with the last Section of Section 3.1.1.

         Landlord and Tenant shall cooperate during the above time periods so
that each party makes the other aware of their progress with respect to the
foregoing plans, selections and pricing, as well as timing, availability or cost
constraints of Tenant's selections or specifications and proposed alternates.

         Landlord shall cause the Premises to be completed in accordance with
Landlord's Plans and Tenant's Plans, all of such work to be performed by
Landlord's general contractor, Gutierrez Construction Co., Inc. After final
approval of Landlord's Plans and Tenant's Plans by Landlord and Tenant, the
Tenant may request changes to Landlord's Work or Tenant's Work (as applicable)
by altering, adding to, or deducting from Landlord's Work or Tenant's Work (as
applicable) as set forth in the agreed form of Landlord's Plans or Tenant's
Plans, as applicable (each such requested change is referred to herein as a
"Change Order"). A Change Order requested by Tenant in Landlord's Work (or in
Tenant's Work as such term is defined in Section 3.1.1 hereof) which affects
Landlord's Work, or Tenant's Work, may also necessitate an adjustment in the
Outside Delivery Date (as defined in Section 3.2 hereof) and may result in
Tenant Alteration Delay Days (as hereinafter defined), in accordance with and
subject to the terms and conditions set forth below. Landlord shall notify
Tenant promptly in writing if such requested Change Order shall result in Tenant
Alteration Delay Days, and therefore an adjustment in the Outside Delivery Date.
In addition, Landlord agrees to provide Tenant, upon Tenant's request, with
sufficient itemization and back-up documentation to facilitate analysis and to
confirm the cost of any such changes in the Landlord's Work or the Tenant's Work
initiated by Tenant. Tenant shall pay to Landlord an amount equal to the actual
cost (as defined in Section 3.1.1 hereof) of Landlord's Work, including the
costs of any such changes initiated by Tenant, less any appropriate credits for
any Landlord's Work deleted, (hereinafter, the "Net Additional Cost of
Landlord's Work"). The Net Additional Cost of Landlord's Work shall be due and
payable to Landlord in the manner provided for in Section 3.1.1 hereof.

         In the event that Tenant requests a Change Order which would, due to
materials or equipment having long delivery times or due to resulting sequencing
delays, and notwithstanding Landlord's diligent efforts, result in a delay in
the Term Commencement Date, then Tenant shall be deemed to have agreed that it
will pay Fixed Rent (as hereinafter provided in Section 4.1) and


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<PAGE>   14


additional rent hereunder for a number of days equal to the actual number of
days (the "Tenant Alteration Delay Days") as certified by Landlord and its
architect, by which the Term Commencement Date would be delayed by such
alterations or additions, giving due consideration to Landlord's obligation to
use diligent efforts to accelerate construction to make up for lost time due to
delays. Landlord agrees to promptly provide Tenant with written notice of such
determination, such notice to include reasonable detail describing the cause of
the delay and the number of Tenant Alteration Delay Days as certified by
Landlord and its architect. Should Tenant and Tenant's Architect disagree with
the calculation of Tenant Alteration Delay Days as hereinabove determined, then
such disagreement shall be resolved pursuant to the provisions of Section 3.6
hereof.

         All Tenant improvements, changes and additions shall be part of the
Premises (and shall remain therein at the end of the Term), except for Tenant's
business fixtures, equipment and personal property (which such personal property
shall include, without limitation, demountable partitions, equipment and
telephone or computer systems), all of which fixtures, equipment and personal
property shall remain the property of the Tenant and shall be removed at the
expiration of the Term; and such other items installed during the initial
construction of the Building or Tenant's Work shall be removed or left as the
Landlord and Tenant agree in writing at the time of Landlord's approval of the
plans and specifications therefor. Landlord acknowledges and agrees that any
wiring placed within the conduits, plenums and interior of the walls of the
Premises shall remain in the Premises following the termination of this Lease.
Landlord agreeing however that any supplemental HVAC units that are in addition
to and not in substitution for upgrades of any HVAC units in the Landlord's
Plans and any emergency generators and UPS systems in addition to and not in
substitution for or upgrades of any emergency generator or UPS system in
Landlord's Plans may be removed by Tenant at the expiration of the Term provided
the Tenant restores the Building to its prior condition, and repairs any damage
to the Building caused by such removal. In addition Tenant may request certain
additional items contained in Tenant Plans to be removable by Tenant upon the
expiration of the Term, which if agreed to by the Landlord, may be removed by
Tenant in accordance with the provisions of this paragraph. Should Landlord fail
to so agree in writing then at Tenant's option the parties shall use the
arbitration procedure set forth in Section 3.6 of this Lease to determine if
removal of such items would normally be allowed as a standard practice in
Suburban Boston office leases. Tenant agrees to repair and restore, at its sole
cost and expense, any damage to the Premises caused by any such removal by
Tenant in accordance with this Section.

3.1.1    TENANT'S WORK.

         So long as Landlord has approved Tenant's Plans in writing, as
hereinabove referenced, Landlord and Tenant agree that Landlord's general
contractor will construct the tenant improvements set forth on the Tenant's
Plans (hereinafter "Tenant's Work") with respect to the Premises at cost (as
hereinafter defined), plus a Landlord's contractor's fee of five and one half
percent (5 1/2%) of such aggregate cost as hereinafter provided. In order to
provide for payment by Tenant of the cost of Tenant's Work, the Net Additional
Cost of Landlord's Work, and any additional costs due to Change Orders provided
for hereunder, Tenant expressly covenants with Landlord that Tenant agrees to
pay Landlord, or its contractor, as the case may be, within ten (10)


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<PAGE>   15


business days of receipt of each of Landlord's monthly Tenant's Work
requisitions therefor, the amount of such requisition for the Tenant's Work, the
Net Additional Cost of Landlord's Work, and/or any Change Orders, performed in
the Premises for the preceding month based on a percentage of completion basis.
Such requisitions shall not include the five (5%) percent retainage of all
payments to be made to subcontractors until such subcontractors have fully
completed their work. At Tenant's request, each requisition shall include copies
of all subcontractor's and supplier's applications for payment and satisfactory
evidence of payment of all previous invoices submitted by subcontractors and
suppliers. In addition, Landlord's architect shall certify that the subject work
specified in each of such monthly requisitions has been substantially completed,
and a copy of such certification shall accompany each requisition furnished to
Tenant hereunder. In the event Tenant's Architect disagrees with the Landlord's
architect's certification as set forth in the immediately preceding sentence,
then such disagreement shall be resolved pursuant to the provisions of Section
3.6 hereof except that the time for each architect to establish the amount in
dispute shall be six (6) calendar days. In no event shall any of such costs due
and payable hereunder remain unpaid by Tenant for more than fifteen (15) days
after receipt of such Landlord's requisition, or as of the Term Commencement
Date.

         For purposes hereof, Landlord and Tenant further agree that the
certification of cost by Gutierrez Construction Co., Inc. shall be based on the
definition of cost as more particularly set forth in Exhibit L hereto. Any
changes to the Tenant's Plans after the approval of the Tenant's Plans (and any
changes to Landlord's Plans after the approval thereof as set forth in Section
3.1 above) shall be in accordance with the form of Change Order attached hereto
as Exhibit K.

         In addition, in the event that Landlord and Tenant are unable to agree
on the cost of any portion of Tenant's Work hereunder, any disagreement shall be
resolved pursuant to the provisions of Section 3.6 hereof.

         Upon commencement of the Tenant's Work, Landlord and Tenant hereby
further agree, each acting reasonably and in good faith, to attend and
participate in weekly construction meetings with Landlord's general contractor's
construction manager(s) during such construction process.

3.1.2    TENANT'S CONSTRUCTION WORK.

         Tenant agrees that any construction included in Tenant's Plans which
Tenant specifies to be done by itself or its contractors (hereinafter referred
to as "Tenant's Construction Work"), which shall include, for example, Tenant's
installation of furnishings, computers, lab equipment, IT/MIS, security and
later changes or additions, shall be completed by and coordinated with any work
being performed by Landlord in such manner as to maintain harmonious labor
relations and not materially damage the Premises, Lot or Park or materially
interfere with the operation of the Building or with any of Landlord's
construction work hereunder, including but not limited to the construction of
the Landlord's Work and Tenant's Work. Tenant shall ensure that its contractors
or subcontractors procure and maintain insurance as required by Tenant's
Contractor's and Subcontractor Minimum Insurance Requirements set forth in
Exhibit "H" to this Lease. Tenant


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<PAGE>   16


(including its contractors, agents or employees) shall have access to the
Premises and may perform Tenant's Construction Work prior to the Scheduled Term
Commencement Date and prior to the commencement of the Term so as to prepare the
Premises for occupancy by Tenant, provided that (i) Tenant's contractors, agents
or employees work in a harmonious labor relationship with Landlord's general
contractor, (ii) reasonable prior written notice is given to Landlord's general
contractor specifying the work to be done, and (iii) no work, as reasonably
determined by Landlord, shall be done or fixtures or equipment installed by
Tenant in such manner as to materially interfere with the completion of
Landlord's Work and the Tenant's Work being done by or for Landlord on the
Premises. During the period of preoccupancy of the Premises by Tenant in
connection with Tenant's Construction Work prior to the commencement of the
Term, no Fixed Rent or additional rent or other charges shall accrue or be
payable, but otherwise such preoccupancy shall be subject to all the terms,
covenants and conditions contained in this Lease.

3.2      PREPARATION OF PREMISES FOR OCCUPANCY.

         Landlord shall perform the construction work set forth in the
Landlord's Plans and the Tenant's Plans, and, therefore, Landlord agrees to use
diligent efforts to have the Premises ready for occupancy on the Scheduled Term
Commencement Date.

         Landlord and Tenant agree that time is of the essence, and Landlord
agrees to use diligent efforts to accelerate construction to make up for time
lost due to any delay. Unless sooner terminated by Tenant pursuant to the
provisions of Section 3.2, the Term of this Lease shall commence on the date the
Premises are deemed ready for occupancy as set forth below (the "Term
Commencement Date").

         The Premises shall be deemed "ready for occupancy" on the earlier of:

         (a) the date on which Tenant occupies all or any portion of the
Premises for the Permitted Uses; or

         (b) (1) the date on which the construction of all of the Landlord's
Work and the Tenant's Work is Substantially Completed, as defined below, and (2)
Landlord has delivered to Tenant copies of all permits and approvals (the
"Permits") required to be obtained from any governmental agency in connection
with the (i) construction of the Building or (ii) prior to occupancy of the
Premises by Tenant, including, without limitation, a permanent certificate of
occupancy from the Town of Bedford or a temporary certificate of occupancy from
the Town of Bedford which allows Tenant to use and occupy the Premises,
including in all cases use of the elevator(s), and which temporary certificate
of occupancy is not conditional on the performance of any work other than the
Punch List Work as defined below, except that such Permits shall not be required
as a condition of Substantial Completion if Landlord is unable to secure the
same due solely to Tenant's failure to complete Tenant's Construction Work as
specified in Section 3.1.2 above (which such date, subject to additional terms
and provisions of this Section 3.2, shall hereinafter be referred to as the date
of "Substantial Completion" or which such work shall hereinafter be referred to
as "Substantially Completed"). In any event, notwithstanding the


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<PAGE>   17


achievement of Substantial Completion, all Punch List Work shall be completed by
no later than sixty (60) days following Substantial Completion, except as
hereinafter provided.

         An AIA Certificate of Substantial Completion by the Landlord's
architect (which such Certificate shall be in the form attached hereto as
Exhibit C-1) shall evidence the Landlord's determination that it has performed
all such obligations, except for completing the landscaping work and completing
the final paving course, and minor items stated in such Certificate to be
incomplete or not in conformity with such requirements, or will not materially
interfere with Tenant's use or occupancy of the Premises and all of which work
shall be identified and specified in the Certificate of Substantial Completion
(collectively such landscaping work, finish paving course work and minor items
are referred to herein as the "Punch List Work") shall be promptly completed.
Tenant shall have the right within fifteen (15) days after Tenant's receipt of
said Certificate of Substantial Completion to notify Landlord of its
disagreement with said Certificate and to identify additional items of Punch
List Work, all of which shall be completed by Landlord no later than April 30,
2002.

         If weather materially and adversely interferes with Landlord's ability
to finish the final course of paving and outside work or such other Punch List
Work, which such work does not materially interfere with Tenant's occupancy, and
the operation of Tenant's business therein, said work can be completed by
Landlord reasonably thereafter, so long as such delay does not and will not
interfere with or prevent Tenant from obtaining a certificate of occupancy upon
completion of all other work herein described.

         After Landlord has completed all Landlord's Work and Tenant's Work,
including all Punch List Work, Landlord's architect shall forward to Tenant its
Certificate of Final Completion, such Certificate to be in the form attached
hereto as Exhibit C-2. In addition, promptly after completion of all such work,
including all Tenant's Construction Work by Tenant, Landlord shall forward to
Tenant a final certificate of occupancy from the Town of Bedford.

         The phrase "Tenant's Delay" shall mean the aggregate number of days
(excluding any days of delay caused by or resulting from Force Majeure) equal to
the actual number of days that, notwithstanding its diligent and good faith
efforts to complete construction by the Scheduled Term Commencement Date, the
Landlord is delayed in completing its construction by the Scheduled Term
Commencement Date due to (i) the failure of the Tenant to deliver the Tenant's
Plans (or portions or modifications thereto) to Landlord on the dates
established pursuant to Section 3.1 hereof, or (ii) a delay caused by Tenant
performing the Tenant's Construction Work pursuant to Section 3.1.2 hereof, or
(iii) a delay or stoppage requested in writing by Tenant, or (iv) the number of
Tenant Alteration Delay Days resulting from Change Orders requested by Tenant
pursuant to Section 3.1 hereof, or (v) the number of Tenant Plan Delay Day(s)
pursuant to Section 3.1 hereof, then the Term Commencement Date shall be deemed
to have occurred on the date, as certified by Landlord and its architect, that
Substantial Completion would have occurred had there not occurred such Tenant's
Delay, calculated by determining the number of days of Tenant's Delay as
aforesaid, giving consideration to Landlord's obligation under the second
Section of this Section 3.2 to accelerate to make up for time lost due to any
delays. Landlord agrees to promptly provide Tenant with written notice of such
Tenant's Delay promptly after the


                                       13

<PAGE>   18


occurrence of such Tenant's Delay, such notice to include reasonable detail
describing the cause of the delay as certified by Landlord's architect.

         Notwithstanding the foregoing provisions, if the Premises are not
deemed ready for occupancy on or before the Outside Delivery Date (as defined
below) for whatever reason, Tenant may elect (i) to cancel this Lease at any
time thereafter while the Premises are not deemed ready for occupancy by giving
notice to Landlord of such cancellation which shall be effective ten (10) days
after such notice, unless within such ten (10) day period Landlord delivers the
Premises ready for occupancy as defined herein, in which event such notice of
cancellation shall be rendered null and void and of no further force or effect,
or (ii) to enforce Landlord's covenants to construct the Premises in accordance
with the terms of this Lease. In the event Tenant elects to enforce Landlord's
agreement to construct the Premises in accordance with this Lease, Tenant shall
also have the right to terminate this Lease if Landlord fails to complete the
Premises within the period of time set by any court of competent jurisdiction
for such work to be completed, or within such additional period of time from the
date of Landlord's default as may be mutually agreed to by Landlord and Tenant.
Notwithstanding any provision of this Lease to the contrary, in the event that
the Premises are not deemed ready for occupancy on or prior to the Scheduled
Term Commencement Date (as such date may be extended for reasons due to Force
Majeure and/or to Tenant's Delay), then Tenant may elect to receive from
Landlord as liquidated damages an abatement of Fixed Rent (following the
commencement of rental obligations pursuant to Section 4.1 hereof) equal to (a)
one hundred percent (100%) of the Fixed Rent for each day the Landlord's Work
and the Tenant's Work is not Substantially Completed forty five (45) days beyond
the Scheduled Term Commencement Date, as such date may be extended as aforesaid,
(b) one hundred twenty-fifty percent (125%) of the Fixed Rent for each day the
Landlord's Work and Tenant's Work is not completed one hundred twenty (120) days
beyond the Scheduled Term Commencement Date (as such date may be extended as
aforesaid). If the Premises are not Substantially Completed and therefore not
deemed ready for occupancy on or before such date which is one hundred sixty
(160) days beyond the Scheduled Term Commencement Date, as such date may be
extended as aforesaid, then Tenant may elect to terminate this Lease or enforce
Landlord's covenants to construct as hereinbefore provided. The foregoing
remedies shall be Tenant's sole and exclusive remedies for not having the
Premises ready for occupancy as required hereunder.

         For purposes hereof, the Outside Delivery Date shall be deemed to refer
to that certain date which is one hundred sixty (160) days following the
Scheduled Term Commencement Date, as such date may be extended for a period
equal to that of (i) any delays due to Force Majeure as defined in Section 3.5
hereof, (ii) the number of delay days caused by a Tenant's Delay as hereinbefore
determined.

3.2.1    PARTIAL OCCUPANCY AND RENT COMMENCEMENT.

         If the entire Premises are not ready for occupancy on the Scheduled
Term Commencement Date, the Tenant may elect, but shall have no obligation to,
occupy any portion or portions of the Premises which are ready for occupancy
when, in Landlord's opinion, it can be done without material interference with
remaining work. In such event, Tenant agrees not to


                                       14

<PAGE>   19


materially interfere with Landlord's construction of the Premises. In the event
Tenant elects to take occupancy of a portion of the Premises, that portion shall
be deemed ready for occupancy as to said portion on the date of occupancy of
such portion and Tenant's obligation to pay Fixed Rent and additional rent shall
commence on said date pro rata based on the square footage occupied compared to
the total square footage in the Premises.

3.3      GENERAL PROVISIONS APPLICABLE TO CONSTRUCTION

         All construction work required or permitted by this Lease, whether by
Landlord or by Tenant (or their respective subcontractors), shall be done in a
good and workmanlike manner and in compliance with all applicable laws and all
lawful ordinances, regulations and orders of governmental authority and insurers
of the Building which laws, ordinances and regulations shall include, but shall
not be limited to the Americans with Disabilities Act of 1990 (ADA), the
Massachusetts State Building Code and the Bedford Massachusetts Zoning By-Laws.
Either party may inspect the work of the other at reasonable times and shall
promptly give notice of observed defects. Notice of said defects shall be in
writing and shall be rectified by Landlord or Tenant, as the case may be, within
thirty (30) days of the original date of notice if capable of being corrected
within such time period, otherwise the correction shall be commenced within such
time period and diligently pursued to completion. Failure to provide notice
hereunder shall not be the basis for any liability or for injury or damage
caused by such defect of or waiver of right to cause any defect to be corrected.

3.4      REPRESENTATIVES

         Landlord hereby acknowledges and agrees that only the following person,
John F. Kennedy or Richard P. White or any successor to either of them holding
the same title or any other person delegated the authority from either of them
in writing (hereinafter "Tenant's Construction Representatives") have the
authority to act on Tenant's behalf and represent Tenant's interest with respect
to all matters requiring Tenant's action in this Article. No consent,
authorization or other action by Tenant with respect to matters set forth in
this Article shall bind Tenant unless in writing and signed by one of the
aforementioned persons. Landlord hereby expressly recognizes and agrees that no
other person claiming to act on behalf of Tenant is authorized to do so. If
Landlord complies with any request or direction presented to it by anyone
claiming to act on behalf of Tenant who does not have the title and position
mentioned above, such compliance shall be at Landlord's sole risk and
responsibility and shall not in any way alter or diminish the obligations and
requirements created and imposed by this Article, and Tenant shall have the
right to enforce compliance with this Article without suffering any waiver or
abrogation of any of its rights hereunder.

         Tenant hereby acknowledges and agrees that only the following persons,
Arturo J. Gutierrez, John A. Cataldo or any successors to either of them holding
the same title or any other person delegated the authority from either of them
in writing (hereinafter "Landlord's Construction Representatives") have the
authority to act on Landlord's behalf and represent Landlord's interests with
respect to all matters requiring Landlord's action in this Article. No consent,
authorization or other action by Landlord with respect to matters set forth in
this Article


                                       15

<PAGE>   20


shall bind Landlord unless in writing and signed by one of the aforementioned
persons. Tenant hereby expressly recognizes and agrees that no other person
claiming to act on behalf of Landlord is authorized to do so. If Tenant complies
with any request or direction presented to it by anyone claiming to act on
behalf of Landlord who does not have the title and position mentioned above,
such compliance shall be at Tenant's sole risk and responsibility and shall not
in any way alter or diminish the obligations and requirements created and
imposed by this Article, and Landlord shall have the right to enforce compliance
with this Article without suffering any waiver or abrogation of any of its
rights hereunder.

3.5      FORCE MAJEURE.

         As used in this Article and elsewhere in the Lease, "Force Majeure"
shall mean a time extension equal to that of any delays when the party required
to perform the respective obligation is prevented from doing so, despite the
exercise of reasonable diligence, and such delay is caused by: (i) Acts of God,
(ii) changes in government regulations, (iii) casualty, (iv) strike or other
such labor difficulties, (v) unusual weather conditions, (vi) unusual scarcity
of or inability to obtain supplies, parts or labor to furnish such services with
no reasonably practical alternatives therefor, or (vii) other acts reasonably
beyond Landlord's control, but in no event shall the term include economic or
financing difficulties. Landlord shall provide Tenant with written notice of the
occurrence of a Force Majeure event promptly after the occurrence thereof, and
shall comply with its respective obligation(s) as soon as the cause for the
delay has (have) been eliminated.

3.6      ARBITRATION BY ARCHITECTS.

         Whenever there is a disagreement between the parties with respect to
construction by Landlord of Landlord's Work or Tenant's Work, such disagreement
shall be definitively determined by the following procedure: Each of Landlord
and Tenant shall appoint one (1) independent architect (which such architect may
be Landlord's Architect and Tenant's Architect referenced in Section 3.1 above),
such two (2) architects will then (within five (5) days of their appointment)
appoint a third independent architect licensed in the Commonwealth of
Massachusetts with not less than fifteen (15) years experience. Each architect
shall establish within ten (10) days of their appointment the matter in dispute.
In case of any dispute with respect to dollar amounts or lengths of time or
dates such as the date of Substantial Completion, the dollar amount or length of
time or date shall be the average of the two closest determinations by the three
(3) architects, with the determination of the architect which was not closest to
another architect's determination excluded from such calculation. In case of any
dispute not involving dollar amounts or lengths of time or dates (i.e. the
approval of plans) the determination by at least two (2) of the three (3)
architects shall be required in order to resolve the matter in dispute. Landlord
and Tenant shall each bear the cost of the architect selected by them
respectively and shall share equally the cost of the third architect. During
such arbitration period, the parties agree to cooperate with one another so as
to proceed with construction and with their respective obligations hereunder in
a timely manner. Each determination under this Section 3.6 shall be binding upon
Landlord and Tenant.


                                       16

<PAGE>   21



3.7      WARRANTY OF LANDLORD'S WORK AND TENANT'S WORK.

         Landlord hereby warrants and guarantees that the Landlord's Work and
the Tenant's Work shall be free from defects in workmanship and materials for a
period of one (1) year after the Term Commencement Date. Upon the expiration of
said one (1) year period, Landlord shall assign to Tenant any and all warranties
and guarantees with respect to Landlord's Work and Tenant's Work and, to the
extent that any such warranties and guarantees are not assignable, Landlord
agrees to enforce the same for the benefit of Tenant, at Tenant's sole cost and
expense. Tenant shall not be responsible to pay for any such warranties of less
than one (1) year duration or enforcement by Landlord against its own employees
or against Gutierrez Construction Co., Inc. or against any of its other
affiliates (including their respective employees). Landlord agrees to repair, at
its sole cost and expense any latent defects in Landlord's Work or Tenant's Work
promptly after receipt of notice therefrom from Tenant, provided that such
notice from Tenant is received by Landlord within said one (1) year period. In
connection therewith, Tenant shall notify Landlord promptly after it becomes
aware of any such latent defects. Any repairs or replacements or alterations to
Landlord's Work or Tenant's Work after said initial one (1) year period shall be
chargeable to Tenant in accordance with and subject to the provisions of Section
4.2 hereof.

         In addition to the foregoing, Landlord hereby warrants that Landlord's
Work upon Substantial Completion will comply with all applicable laws then in
effect and as interpreted on the date of Substantial Completion, including but
not limited to all applicable building codes, governmental requirements and the
regulations of the Americans with Disabilities Act of 1990 (ADA) for a period of
one (1) year after the Term Commencement Date. Upon the expiration of said one
(1) year period, Landlord agrees to assign to Tenant any and all warranties and
guarantees with respect to Landlord's Work and any claims that Landlord may have
against any subcontractors for their failure to design or construct the
Landlord's Work in compliance with all applicable laws in effect and as
interpreted on the date of Substantial Completion, including but not limited to
all applicable building codes, governmental requirements and the regulations of
the Americans with Disabilities Act of 1990 (ADA) to the extent such warranties,
guarantees and claims are not assignable, Landlord agrees to use reasonable
efforts, at Tenant's sole cost and expense, to enforce the same for the benefit
of Tenant. Tenant shall not be responsible to pay for any such enforcement
during the one (1) year period following the Term Commencement Date or
enforcement by Landlord against its own employees or against Gutierrez
Construction Co., Inc. or against any of its other affiliates (including their
respective employees).

3.8      TENANT'S CONTRIBUTION TO LANDLORD'S WORK

         Tenant has elected to contribute Two Million Eight Hundred Twenty-three
Thousand Three Hundred Dollars ($2,823,300) (i.e., $15.00/s.f.) toward the cost
of Landlord's Work ("Tenant Contribution to Landlord's Work.") In consideration
thereof, Landlord has reduced the Fixed Rent payable in each year of the Initial
Term of this Lease by Three Hundred Four Thousand Nine Hundred Sixteen Dollars
and Forty Cents ($304,916.40) (i.e., $1.62/s.f.) per year during each year. Such
Fixed Rent as reduced by said amounts is set forth in Section 1.1 of this


                                       17

<PAGE>   22


Lease. Such Rent Reduction is calculated on the basis of Two Million Eight
Hundred Twenty-three Thousand Three Hundred Dollars ($2,823,300) times (x) .108.
If there was no Tenant Contribution to Landlord's Work, the Fixed Rent that
would otherwise be payable hereunder during the Initial Term would be as
follows: Years 1 through 3: $19.25 per square foot; Years 4 through 6: $21.25
per square foot; Years 7 through 10: $24.25 per square foot; and Years 11
through 15: $28.25 per square foot. Any determination of the rent for any
Expansion Building or Expansion Premises, as the same are defined in Exhibits
"Q" and "R" under Tenant's Expansion Options, Rights of First Refusal, or
Extensions under the terms of this Lease shall be calculated on the basis of the
unreduced rents set forth in the immediately preceding sentence rather than the
Fixed Rent set forth in Section 1.1 of this Lease which reflects the reduction
thereof in recognition of Tenant Contribution to Landlord's Work for this
Building. Any reduction of Fixed Rent payable for such Expansion Building(s), or
Expansion Premises, or Extension, if any, shall be calculated after the
determination of Fixed Rent for any such Expansion Building(s), or Expansion
Premises, or Extension as provided in the applicable Exhibit to this Lease.

         Such Tenant Contribution to Landlord's Work will be paid to Landlord
within fifteen (15) days of Substantial Completion of the Building. In order to
guarantee Tenant's obligation to make such Contribution toward the cost of
Landlord's Work, Tenant shall, on or before ten (10) business days following the
execution of this Lease by both parties, provide an irrevocable letter of credit
satisfactory in form and substance to Landlord's proposed construction mortgagee
payable to Landlord and assignable to Landlord's construction mortgagee and its
assigns in the amount of Two Million Eight Hundred Twenty-three Thousand Three
Hundred Dollars ($2,823,300). The failure of the Tenant to provide such letter
of credit to the Landlord within said timeframe, or the failure of the Tenant to
pay to Landlord the Tenant Contribution to Landlord's Work, as specified herein,
shall be an event of default under this Lease.

                                   ARTICLE IV
                                      RENT

4.1      RENT

         Tenant agrees to pay, without any offset or reduction, except as
expressly set forth in Section 3.2, 7.1 or 7.2, Fixed Rent equal to 1/12th of
the annual Fixed Rent in the monthly installments set forth in Section 1.1 in
equal installments in advance on the first day of each calendar month included
in the Term; and for any portion of a calendar month occurring at the beginning
or end of the Term, at the rate payable for such portion in advance.

4.2      OPERATING COST REIMBURSEMENT

         Tenant shall pay to Landlord, as additional rent for Landlord's
Operating Costs, an additional payment on the first day of each month occurring
during the Term hereof one-twelfth (1/12) of the amount of estimated annual
Landlord's Operating Costs and estimated annual Real Estate Taxes.

         4.2.1  The Landlord's Operating Costs shall include, without
limitation:


                                       18

<PAGE>   23


         (A) The following Building and Lot services which shall be provided by
Landlord: Building and Lot Expenses such as but not limited to (i) the
operation, maintenance and repair of the Building parking lot, Building parking
lot lighting and exterior lighting for the Building and for the Building drives;
(ii) snow removal and sanding of the Building drives and parking lots
specifically not including shoveling and snow removal, sanding and sweeping of
Building or Lot sidewalks which shall be the responsibility of Tenant; (iii)
maintenance and repair of roadways and driveways within the Lot; (iv)
maintenance and repair of exterior sewer, utility and drainage facilities on the
Lot; (v) maintenance and repair of detention areas, ground water recharge areas,
and exterior fire main and exterior fire hydrant facilities on the Lot; (vi)
striping, changing of street and parking lot lamp-post lights on any portion of
the Lot and keeping the same in proper working condition; (vii) fertilization,
mowing and watering of lawns and landscaping, care of shrubbery and general
grounds upkeep on any portion of the Lot (viii) cleaning exterior windows; (ix)
maintaining the caulking, or recaulking of the windows, the precast panels, or
other portions of the Building exterior (specifically excluding Landlord's
structural obligations); (x) obtaining and maintaining real property and rental
interruption special form insurance, including earthquake and flood insurance as
well as commercial general liability insurance on the Building, and "all risk"
insurance, including earthquake and fire coverage on the Building as required by
article 5.1.6 of this Lease. The cost of all such insurance coverage obtained by
the Landlord shall be included in the Landlord's Operating Costs; (xi) after the
initial ten (10) years of Term, the cost of repairing and maintaining and
replacing the roof shall be included in Landlord's Operating Costs; and (xii)
all other reasonable and necessary expenses paid in connection with the
operation, cleaning, maintenance, and repair of the Building and Lot or Park, or
either, and properly chargeable against income, it being agreed that if Landlord
installs a new or replacement capital item for the purpose of reducing
Landlord's Operating Costs (provided Landlord reasonably anticipates such new or
replacement capital item will reduce Landlord's Operating Costs), the costs
thereof as reasonably amortized by Landlord over the useful life in years of the
capital item so installed with legal interest on the unamortized amounts, shall
be included in Landlord's Operating Costs, except as otherwise set forth below
to the contrary. Landlord agrees that all of such services to be included in
Landlord's Operating Costs shall be obtained by Landlord at commercially
reasonable, competitive market rates consistent with the operation and
management of comparable "Class A" office buildings in the suburban Boston area.
Tenant may participate with Landlord in the section of all major service
provider contracts for the Building so as to help control both the cost and
quality of service provided to the Building, so long as Tenant is leasing at
least seventy-five percent (75%) of the Building and is not then in default of
this Lease beyond applicable cure periods, if any, and;

         (B) All Park Services to be provided by the Landlord: Park Expenses,
such as but not limited to, (i) lighting for the Park Common Areas; (ii) snow
removal and sanding and maintenance and repair of roadways and driveways within
the Park Common Areas; (iii) maintenance and repair of common Park exterior
sewer, utility, and drainage facilities; (iv) maintenance and repair of common
Park detention, ground water recharge areas, and exterior fire main and exterior
fire hydrant facilities; (v) striping, changing of street and common drive lamp
post lights, electrical charges for same, and keeping the same in proper working
condition, (vi) lighting, traffic signals, electrical costs of the foregoing,
and traffic control personnel for the


                                       19

<PAGE>   24


park; (vii) fertilization, mowing and watering of lawns and landscaping, care of
shrubbery and general grounds upkeep on common portion of the Park; (viii)
operating Landlord's or the Park's Transportation Demand Management Plan as
required by the Park covenants as set forth in Exhibit "I" hereto, (ix)
obtaining and maintaining commercial general liability insurance covering the
Common Areas of the Park. The Park common areas shall be maintained in a
first-class manner, similar to office/R&D parks in the
Billerica/Bedford/Burlington Massachusetts area.

         Allocation for the Park Common Areas shall be based upon the share of
such costs allocated to the Lot based on the ratio of the square footage of the
Building to the aggregate square footage of all buildings on all lots in the
Bedford Woods Park, and with respect to the costs of snow removal and sanding
and with respect to maintenance of traffic signals and traffic control
personnel, such costs shall be allocated by Landlord on a reasonable basis
taking into consideration the usage of the roadways and the necessity of
additional snow removal and sanding due to overtime and weekend use of certain
buildings within The Bedford Woods Park, and such other pertinent factors as
reasonably determined by Landlord, subject to Tenant's approval, not to be
unreasonably withheld, delayed or conditioned.

         Landlord's Operating Costs as used herein shall mean the sum of one
hundred percent (100%) of the expenses for Landlord's maintenance and repair
obligations related to the Building and its Lot as set forth in Section 4.2.1 A
above, exclusive of utilities which shall be paid by Tenant as provided in this
Article 4.2.3, plus a pro rata share for the Park Common Area Expenses as set
forth in Section 4.2.1 B above, which total shall constitute "Landlord's
Operating Costs".

         Notwithstanding anything to the contrary in this Lease contained,
Tenant shall not be required to pay Landlord's Operating Costs for:

         (a)      repairs which are the responsibility of the Landlord,
                  including repairs required to be completed by Landlord as set
                  forth in Section 3.7 of this Lease, structural repairs, as
                  well as repairs or other work occasioned by fire or other
                  casualty, not caused by the negligence or willful action of
                  Tenant, or by the exercise of eminent domain, or any work
                  required for Landlord to comply with its construction
                  guarantees;

         (b)      any leasing commissions;

         (c)      any attorney's fees, costs and disbursements and other
                  expenses incurred in connection with negotiations or disputes
                  with other tenants, occupants or prospective tenants or
                  occupants of the Building or Park;

         (d)      interest, principal, ground rent, or other payments under any
                  mortgage, ground lease or other financing or refinancing of
                  the Building, the Lot or the Park;

         (e)      any advertising or promotional expenditures;


                                       20

<PAGE>   25


         (f)      overhead or profit increment paid to subsidiaries or
                  affiliates of Landlord for services on or to the Premises to
                  the extent that the costs of such services exceed competitive
                  costs of such services were they not so rendered by a
                  subsidiary or affiliate; and

         (g)      real estate taxes for any other lot or building within the
                  Park, except to the extent such real estate taxes relate to
                  certain land or building(s) which benefit Tenant and are
                  appurtenances to the Building (by way of example but not
                  limitation, detention basins serving the Lot, driveways,
                  roads, and sidewalks).

         (h)      Costs of corrective defects in the Building or the Building
                  equipment or replacing defective equipment solely to the
                  extent such costs relate to items covered by warranties of
                  manufacturers, suppliers or contractors or are otherwise borne
                  by parties other than Landlord and for which Landlord receives
                  full reimbursement provided, however, the cost of correcting
                  any defects in the Landlord's Work and Tenant's Work in the
                  first year following the Term Commencement Date as set forth
                  in Section 3.7 of this Lease shall be excluded from Landlord's
                  Operating Costs.

         (i)      Costs of installations paid by or constructed for specific
                  other tenants, other than Tenant, or other occupants of the
                  Building or the Park.

         (j)      All amounts which are specifically charged to or otherwise
                  paid by any other tenant or other occupant of the Building or
                  the Park, or for items or services which Landlord provides
                  selectively to one or more tenants (other than Tenant) without
                  reimbursement.

         (k)      Any bad debt loss, rent loss or reserves for bad debts or rent
                  loss.

         (l)      Expenses related to third-party landlord-tenant disputes.

         The initial payments for the first calendar year will be based on the
budgets for Landlord's Operating Costs heretofore provided to Tenant, which may
be adjusted as provided in this Section 4.2.

         Tenant shall receive from Landlord within five (5) months of the end of
each calendar year an annual accounting, in writing, of actual charges and shall
have access to the Landlord's records at reasonable times with prior written
notice to verify these charges. If the funds were not fully spent, the Landlord
shall then promptly provide for a rebate to Tenant of all unspent funds within
thirty (30) days of such accountings, and if Landlord's Operating Costs fund was
insufficient to pay such charges, the Tenant shall pay any deficiency to the
Landlord within thirty (30) days of billing by Landlord. Landlord reserves the
right to adjust the estimated Landlord's Operating Costs annually effective on
the first day of each calendar year during the Term hereof upon thirty (30) days
prior written notice to Tenant and upon prior receipt by Tenant of


                                       21

<PAGE>   26


documentation evidencing the reasons for such change. Any such change shall be
effective retroactively to the first day of the calendar year during which the
adjustment is made.

         Notwithstanding anything contained herein, Landlord reserves the right
to separately invoice Tenant during the calendar year for Tenant's share of any
actual expense for items reasonably beyond the Landlord's control contained in
the Landlord's Operating Costs fund which exceeds the amount for such item in
the estimated Landlord's Operating Costs for that year by greater than five
percent (5%) provided: (a) that such special invoicing shall be no more frequent
than twice annually, and (b) that Tenant shall have sixty (60) days to make
payment thereon.

         If the total of the monthly payments paid by Tenant with respect to any
Fiscal Year exceeds the actual Operating Cost Escalation for such Fiscal Year,
then, at Landlord's option, such excess shall be either (i) credited against
payments on account of Operating Cost Escalation next due hereunder, or (ii)
refunded by Landlord to Tenant.

         The term "Fiscal Year" as used in this Article shall mean the period of
twelve (12) consecutive months commencing on January 1 and ending on December
31.

         4.2.2 REAL ESTATE TAXES - Tenant shall pay to Landlord as Additional
Rent the Real Estate Taxes within ten (10) days prior to the due date of any
Real Estate Tax bill. In the event the mortgagee on the Property requires the
Real Estate Taxes to be escrowed, Tenant agrees to pay to Landlord as Additional
Rent with the Fixed Rent payment on the first date of each calendar month
included in the Term, one twelfth (1/12) of the Real Estate Taxes. The Term
"Real Estate Taxes" as used above shall mean all taxes of every kind and nature
assessed by any governmental authority on the Lot, the Building and
improvements, or both, and on the Common Areas of the Park which the Landlord
shall become obligated to pay because of or in connection with the ownership,
leasing and operating of the Lot, the Building and improvements, or both,
subject to the following: There shall be excluded for such taxes all income
taxes, excess profits taxes, excise taxes, franchise taxes, estate, succession,
inheritance and transfer taxes, provided, however, that if at any time during
the Term the present system of ad valorem taxation of real property shall be
changed so that in lieu of the whole or any part of the ad valorem tax on real
property, there shall be assessed on Landlord a capital levy or other tax on the
gross rents received with respect to the Lot, Building and improvements, or
both, and the Common Areas of the Park, a federal, state, county, municipal, or
other local income, franchise, excise or similar tax, assessment, levy or charge
(distinct from any now in effect) measured by or based, in whole or in part,
upon any such gross rents, then any and all of such taxes, assessments, levies
or charges, to the extent so measured or based, shall be deemed to be included
within the term "real estate taxes". Landlord agrees to promptly give Tenant
notice of any Real Estate Tax bills received by Landlord. Tenant shall have the
right, upon prior notice to Landlord, to seek an abatement of or contest or
review by legal proceedings or otherwise any such Taxes, and at the request of
Tenant, Landlord shall join and otherwise cooperate in any such proceedings,
provided that Tenant shall defend, indemnify and save harmless Landlord from and
against any cost or expense incurred by Landlord in connection with any such
proceedings. Tenant shall be entitled


                                       22

<PAGE>   27


to any rebate or refund of Taxes received by Landlord or Tenant to Taxes in
respect of the Premises for the Term of the Lease.

         The amount of any refund of real estate taxes shall be credited against
real estate taxes for the Fiscal Year in which such refund is received;
provided, however, in the event that Landlord receives a refund on account of
real estate taxes after the expiration of the Term, which refund relates to a
Fiscal Year during the Term, the amount of such refund fairly allocable to
Tenant shall be refunded to Tenant by Landlord. All references to real estate
taxes "for" a particular Fiscal Year shall be deemed to refer to real estate
taxes due and payable during such Fiscal Year without regard to when such
impositions are assessed or levied.

         Notwithstanding any language to the contrary contained herein,
Landlord's Operating Costs shall be reduced by reimbursements, credits,
discounts, reductions or other allowances received or receivable by Landlord for
items of cost included in Landlord's Operating Costs (except for reimbursements
to Landlord by tenants under the additional rent provisions of their respective
leases), including any tax refunds realized as a result of any abatement
proceeding or otherwise. Landlord hereby covenants and agrees that, provided
Tenant has paid Real Estate Taxes to Landlord in a timely manner as hereunder
set forth, Landlord will pay such Real Estate Taxes to the taxing authority when
the same are due and payable.

         4.2.3 UTILITIES - Tenant shall pay directly to the proper authorities
charged with the collection thereof all deposits and charges for water, sewer,
gas, electricity, telephone and other utilities or services used or consumed on
the Premises, whether called charge, tax, assessment, fee or otherwise,
including, without limitation, water and sewer use charges and taxes, if any,
all such charges to be paid as the same from time to time become due, which
bills shall be placed in Tenant's name and billed directly by the respective
utilities to Tenant, Landlord reserving the right to pay such bills if unpaid by
Tenant beyond any applicable grace period, and to recover such payment from
Tenant with any interest and/or penalties chargeable thereon as Additional Rent.

         All records that the Landlord is required to maintain hereunder shall
be maintained by the Landlord for a period of two (2) years following the
expiration of the Fiscal Year to which such records relate. Tenant shall have
the right, through its representatives, to examine, copy and audit such records
at reasonable times, but no more than once per Fiscal Year, upon not less than
ten (10) days prior written notice. Such records shall be maintained at
Landlord's Address set forth in Section 1.1, or such other place within the
Commonwealth of Massachusetts as Landlord shall designate from time to time for
the keeping of such records. The costs of such audits shall be borne by Tenant;
provided, however, that if such audit establishes that the actual Operating Cost
for the Fiscal Year in question is less than the Landlord's final determination
of the Operating Cost as set forth in the Landlord's Statement submitted to
Tenant by at least six (6%) percent, then Landlord shall pay the reasonable cost
of such audit. If, as a result of such audit, it is determined that Tenant must
pay additional amounts to Landlord on account of the Operating Cost, or that
Tenant has overpaid Landlord on account of the Operating Cost, then the
undercharged or overpaid party shall reimburse the other party for the payment
due, together with


                                       23

<PAGE>   28


interest thereon from the date of Landlord's Statement at the interest rate set
forth in Section 4.3 hereof.

         Notwithstanding anything contained to the contrary in this Lease, the
initial responsibility for the payment of all real estate taxes with respect to
the Building and the Park shall be upon the Landlord and the Landlord agrees to
pay the same as required by law. Landlord shall provide Tenant with a
computation of Tenant's pro rata share thereof, and upon Tenant's request,
copies of all tax bills.

         Landlord shall have the right from time to time to change the periods
of accounting under this Section 4.2 to any annual period other than the Fiscal
Year and upon any such change all items referred to in this Section shall be
appropriately apportioned. In all Landlord's Statements, rendered under this
Section, amounts for periods partially within and partially without the
accounting periods shall be appropriately apportioned, and any items which are
not determinable at the time of a Landlord's Statement shall be included therein
on the basis of Landlord's estimate, and with respect thereto Landlord shall
render promptly after determination a supplemental Landlord's Statement, and
appropriate adjustment shall be made according thereto.

         Notwithstanding any other provision of this Section 4.2, if the Term
expires or is terminated as of a date other than the last day of a Fiscal Year
at the end of the Term, Tenant's last payment to Landlord under this Section 4.2
shall be made on the basis of Landlord's best estimate of the items otherwise
includable in Landlord's Statement and shall be made on or before the later of
(a) ten (10) days after Landlord delivers such estimate to Tenant, or (b) the
last day of the Term, with an appropriate payment or refund to be made upon
submission of Landlord's Statement. Without limitation, the obligation of Tenant
to pay the Operating Cost with respect to any Fiscal Year during the Term (or
portion thereof) shall survive the expiration or earlier termination of the
Term.

4.3      PAYMENTS

         All payments of Fixed Rent and additional rent shall be made to
Managing Agent, or to such other person as Landlord may from time to time
designate in writing. If any installment of rent, Fixed Rent or additional, or
on account of leasehold improvements is paid more than five (5) days after the
due date thereof, at Landlord's election, it shall bear interest at the rate of
the prime rate of Fleet National Bank or a major New York Bank selected by
Landlord plus five (5) percent per annum (or, if lower, the maximum rate
permitted by law).


                                       24

<PAGE>   29


                                    ARTICLE V
                              LANDLORD'S COVENANTS

5.1      LANDLORD'S COVENANTS DURING THE TERM

         Landlord covenants during the Term:

         5.1.1    Building Services - To furnish, through Landlord's employees
                  or independent contractors, the services set forth in Section
                  4.2.1 hereof;

         5.1.2    Additional Building Services - To furnish, through Landlord's
                  employees or independent contractors, reasonable additional
                  Building operation services upon reasonable advance request of
                  Tenant at reasonable and competitive rates from time to time
                  established by Landlord to be paid by Tenant;

         5.1.3    Repairs - Except as otherwise provided in Article VII, or
                  except as resulting from Tenant's negligence, overloading or
                  misuse, or by Tenant's failure to perform its obligations
                  under the Lease, except as resulting from settling or sagging
                  within standard engineering tolerance (provided that the
                  settling or sagging does not affect the surface or structural
                  integrity of the Building or in any way materially affect the
                  ordinary and customary use of the Premises, or any part
                  thereof by Tenant), or except for damage or deterioration
                  resulting from reasonable wear and damage, Landlord shall keep
                  in good order, condition and repair, the roof of the Building,
                  all gutters and downspouts, foundations, exterior (including
                  exterior painting and finish) and structural portions of the
                  Building, all building systems serving the Building, and all
                  plumbing and utility lines serving the Premises, whether
                  located within or outside of the Premises. The Landlord's
                  obligations shall include, without limitation, the obligation
                  to make all necessary repairs, replacements or alterations to
                  the roof, the exterior walls, the foundation, the floor slabs
                  and all other structural elements of the Building, as well as
                  caulking windows and precast panels and other portions of the
                  Building exterior, to clean the exterior windows of the
                  building to maintain the Building Parking Area and to maintain
                  in good order and condition the other buildings and
                  improvements located within the Park, including but not
                  limited to the Common Areas of the Park. Landlord shall also
                  maintain, repair and replace the rooftop HVAC equipment
                  (specifically excluding all interior portions of the HVAC
                  system including but not limited to VAV boxes, duct work,
                  circulating pumps control systems, in the Building) in
                  accordance with the requirements of the Landlord's Plans and
                  Tenant's Plans, and shall assign (to the extent assignable)
                  all warranties and guarantees with respect thereto to Tenant.
                  Tenant may elect, at its cost and expense and upon the prior
                  consent of Landlord (which such consent shall not be
                  unreasonably withheld or delayed), to bring actions to enforce
                  remedies under said warranties or guarantees in the name of
                  the Landlord or jointly with Landlord, at no expense to
                  Landlord;


                                       25

<PAGE>   30


         5.1.4    Quiet Enjoyment - That Landlord has the right to make this
                  Lease and that Tenant, on paying the rent and performing its
                  obligations hereunder, shall peacefully and quietly have, hold
                  and enjoy the Premises throughout the Term without any manner
                  of hindrance or molestation from Landlord or anyone claiming
                  under Landlord, subject, however, to all the terms and
                  provisions hereof;

         5.1.5    Intentionally Deleted.

         5.1.6    Landlord's Insurance - Beginning with the commencement of
                  Landlord's Work and thereafter throughout the Term, Landlord
                  shall purchase and keep in force, broad-form commercial
                  general liability insurance, or the equivalent then-customary
                  form providing comparable coverages, written out on an
                  occurrence basis containing provisions adequate to protect the
                  Landlord from and against claims for bodily injury, including
                  death and personal injury and claims for property damage
                  occurring within the Park and/or the Building, such insurance
                  having body injury and property damage combined limits of not
                  less than five million dollars ($5,000,000) per occurrence. In
                  addition, Landlord, for itself and for Tenant as an additional
                  insured as their interest may appear, shall procure and
                  continue in force during the Term, as the same may be extended
                  hereunder, fire and extended coverage insurance, including
                  vandalism, sprinkler leakage and malicious mischief, upon the
                  Building on a full replacement cost basis and upon the
                  Tenant's Work installed initially by the Landlord in the
                  Building on a full replacement cost basis; agreed cost value
                  endorsement with agreed values for the Building and other
                  tenant improvements and alterations, as determined annually by
                  the Landlord's insurer. Landlord shall also procure and
                  continue in force during the Term, as the same may be extended
                  hereunder, (i) rental interruption insurance for twelve (12)
                  months or the maximum amounts permitted, and (ii) Pollution
                  and Remediation Legal Liability insurance. Copies of
                  certificates of insurance evidencing the foregoing shall be
                  furnished to Tenant, upon Tenant's reasonable request. All
                  insurance required of Landlord pursuant to this Section shall
                  be effected under policies issued by insurers or recognized
                  responsibility (which are rated A or A+ by Best's Rating
                  Service or a comparable rating by an equivalent service). The
                  coverages required by this Section 5.1.6 may be provided by a
                  single "package policy";

         5.1.7    Landlord's Indemnity - Landlord covenants and agrees to
                  defend, with counsel reasonably acceptable to Tenant, save
                  harmless and indemnify Tenant from any liability for injury,
                  loss, accident or damage to any person or property on the
                  Premises or the Park, and from any claims, actions,
                  proceedings and reasonable expenses and costs in connection
                  therewith (including, without implied limitation, reasonable
                  counsel fees), arising directly from the negligence acts
                  and/or gross misconduct of Landlord and not caused directly by
                  the negligent acts or gross misconduct of Tenant. In no event
                  shall Landlord be obligated to indemnify Tenant for any
                  willful or negligent act or omission of Tenant or of any of
                  Tenant's employees, agents, contractors or licensees;


                                       26

<PAGE>   31


         5.1.8    Hazardous Materials - Landlord represents and warrants that,
                  to the best of Landlord's knowledge as of the date of this
                  Lease (i) there does not exist any leak, spill, release,
                  discharge, emissions or disposal of Hazardous Materials on the
                  Lot (including the Building to be located thereon), and (ii)
                  the Premises do not (and will not as of the date of
                  Substantial Completion) contain any Hazardous Materials,
                  except as may be specified in Tenant's Plans or as may be
                  contained in customary cleaning supplies or in such other
                  supplies that are necessary for Landlord to perform its
                  obligations hereunder. In the event that any such leak, spill,
                  release, discharge, emission or disposal of Hazardous
                  Materials shall occur on the Lot or (apart from DE MINIMIS
                  amounts of such materials used for cleaning and maintenance
                  purposes or in connection with the operation of loading docks)
                  the Building as result of any negligent acts or gross
                  misconduct of Landlord, Landlord shall take any and all
                  actions necessary to bring the Premises, and/or the Building
                  (excluding all portions thereof leased or leasable to tenants)
                  into compliance with applicable law and other governmental
                  requirements relating thereto.

                  Landlord agrees to notify Tenant immediately upon discovery of
                  any Hazardous Materials on the Premises and to indemnify,
                  defend and hold harmless Tenant and its officers, employees
                  and agents from and against any claims, judgments, damages,
                  penalties, fines, costs, liabilities or loss which arise (a)
                  before the commencement of the Term and (b) during or after
                  the Term from or in connection with the presence or suspected
                  presence of Hazardous Materials on the Premises or in the Park
                  caused directly by the negligent acts or gross misconduct of
                  Landlord. In no event shall Landlord be obligated to indemnify
                  Tenant for any Hazardous Materials which arise, as a result of
                  the negligent acts or gross misconduct of Tenant, its
                  officers, employees, agents, contractors or licensees. The
                  covenants and indemnifications set forth in this Section 5.1.8
                  shall survive the expiration or earlier termination of this
                  Lease; and

         5.1.9    Tenant's Costs - In case Tenant shall, without any fault on
                  its part, be made party to any litigation commenced by or
                  against Landlord or by or against any parties in possession of
                  the Premises or any part thereof claiming under Landlord,
                  Landlord agrees to reimburse Tenant for all reasonable costs,
                  including without implied limitation, reasonable counsel fees,
                  incurred by or imposed upon Tenant in connection with such
                  litigation and to pay all such reasonable costs and fees
                  incurred in connection with the successful enforcement by
                  Tenant of any obligations of Landlord under this Lease.

         5.1.10   Park Common Areas - To maintain the Building Park Area, Lot
                  and Common Areas of the Park in the same manner as other first
                  class office parks in the Bedford or Billerica, Massachusetts
                  area.

                                       27

<PAGE>   32


         Except as specifically provided to the contrary in Section 4.2,
Landlord shall charge Tenant under the provisions of Section 4.2 for the costs
incurred by Landlord in connection with the services and/or repairs set forth in
Sections 5.1.1, 5.1.2, 5.1.3 5.1.6 and 5.1.10 above; provided, however, Landlord
shall be responsible to pay the following, at its sole cost and expense: (i)
replacements which are necessary to maintain the structural integrity of the
Building and (ii) during the initial ten (10) years of the Term, the water tight
integrity of the roof, reasonable wear and tear and damage and destruction due
to casualty or eminent domain or resulting from Tenant's negligence, or misuse,
or overloading as prohibited by Section 6.12, or by reason of Tenant's use of
the Premises other than for the Permitted Uses of the Lease, or by Tenant's
failure to perform its obligations under the Lease, or resulting from actions of
Tenant, Tenant's contractors, or Tenant's subcontractors which damage the roof
or wall systems or otherwise void or impair any then existing roof guarantees or
warranties excepted and (iii) maintenance and repairs (and replacements, if
necessary) covered by Landlord's or manufacturers warranties described in
Section 3.7 above.

5.2      INTERRUPTIONS

         Except as otherwise set forth in Article VII Landlord shall not be
liable to Tenant for any compensation or reduction of rent by reason of
inconvenience or annoyance or for loss of business arising from power losses or
shortages or from the necessity of Landlord's entering the Premises for any of
the purposes in this Lease authorized, or for repairing the Premises or any
portion of the Building or Lot. In case, notwithstanding Landlord's diligent
efforts in connection therewith (which such efforts shall never obligate
Landlord to pay for overtime and/or premium time work, or to pay a premium for
expedited delivery, except as such additional costs are so authorized and paid
for by Tenant), Landlord is prevented or delayed from making any repairs,
alterations or improvements, or furnishing any service or performing any other
covenant or duty to be performed on Landlord's part, by reason of any cause
reasonably beyond Landlord's control (expressly excluding Landlord's financial
inability), Landlord shall not be liable to Tenant therefore, nor, except as
expressly otherwise provided in Article VII, shall Tenant be entitled to any
abatement or reduction of rent by reason thereof, nor shall the same give rise
to a claim in Tenant's favor that such failure constitutes, actual or
constructive, total or partial, eviction from the Premises.

         Landlord reserves the right to stop any service or utility system when
necessary by reason of accident or emergency or until necessary repairs have
been completed. Except in case of emergency repairs, Landlord will give Tenant
reasonable advance notice of any contemplated stoppage and will use reasonable
efforts to avoid unnecessary inconvenience to Tenant by reason thereof.


                                       28

<PAGE>   33



                                   ARTICLE VI
                               TENANT'S COVENANTS

6.1      TENANT'S COVENANTS DURING THE TERM

         Tenant covenants during the Term:

         6.1.1    Tenant's Payments - To pay when due (a) all Fixed Rent and
                  additional rent, (b) all taxes which may be imposed on
                  Tenant's personal property in the Premises (including, without
                  limitation, Tenant's fixtures and equipment) (c) directly to
                  the utility provider (if not payable to Landlord), subject
                  however, to Tenant's right to contest and seek abatement
                  thereof, all charges by public utility for electricity, gas,
                  telephone and other utility services (including service
                  inspections therefor and the charges as may be imposed
                  pursuant to Exhibit D hereof) rendered to the Premises and (d)
                  as additional rent, all reasonable charges of Landlord for
                  services rendered pursuant to Section 5.1.1, 5.1.2, 5.1.3,
                  5.1.6 and 5.1.10 hereof, except as set forth in the last
                  Section of Section 5.1.

         6.1.2    Repairs and Yielding Up - Except as otherwise provided in
                  Article VII and Section 5.1.3, to keep the interior,
                  non-structural elements of the Premises in good order, repair
                  and condition, reasonable wear and damage or destruction by
                  casualty or eminent domain excepted, and at the expiration or
                  termination of this Lease peaceably to yield up the Premises
                  and all changes and additions therein in such order, repair
                  and condition, first removing all goods and effects of Tenant
                  and any items, the removal of which is required by Sections
                  3.1 or 6.1.15 or by agreement or specified therein to be
                  removed at Tenant's election and which Tenant elects to
                  remove, and repairing all damage caused by such removal and
                  leaving them clean and neat; any property not so removed shall
                  be deemed abandoned and may be removed and disposed of by
                  Landlord, in such manner as Landlord shall determine, and
                  Tenant shall pay Landlord the entire reasonable cost and
                  expense incurred by it by effecting such removal and
                  disposition;

         6.1.3    Occupancy and Use - To use and occupy the Premises only for
                  the Permitted Uses; and not to injure or deface the Premises,
                  Building or Lot; and not to permit in the Premises any auction
                  sale, nuisance, or the emission from the Premises of any
                  objectionable noise or odor, nor to permit any use thereof
                  which is improper, offensive, contrary to law or ordinances,
                  or liable to invalidate or increase the premiums for any
                  insurance on the Building or its contents or liable to render
                  necessary any alteration or addition to the Building, unless
                  Tenant agrees to pay such increased premiums and/or costs, and
                  such use (if other than Permitted Uses) is approved by
                  Landlord in advance;

         6.1.4    Rules and Regulations - To comply with the Rules and
                  Regulations set forth in Exhibit E and all other reasonable
                  Rules and Regulations hereafter made by


                                       29


<PAGE>   34

                  Landlord, of which Tenant has been given notice, for the care
                  and use of the Building, Lot and Common Areas of the Park (and
                  their facilities and approaches as further described in the
                  Park Covenants attached hereto as Exhibit I), it being
                  understood that Landlord shall not be liable to Tenant for the
                  failure of other tenants of the Building or Park to conform to
                  such Rules and Regulations; provided that (i) such Rules and
                  Regulations are enforced in a non-discriminatory fashion, and
                  (ii) such Rules and Regulations do not materially interfere
                  with Tenant's use of the Premises and the Building Parking
                  Area.

         6.1.5    Compliance with Laws and Safety Appliances - To keep, from and
                  after the initial installation thereof by Landlord, the
                  Premises equipped with all safety appliances required by law
                  or ordinance or any other regulation of any and public
                  authority and to procure and comply with all licenses and
                  permits so required, it being understood that the foregoing
                  provisions shall not be construed to broaden in any way
                  Tenant's Permitted Uses. Tenant shall have the right, upon
                  giving notice to the Landlord, to contest any obligation
                  imposed upon it pursuant to the provisions of this Section
                  6.1.5, and provided the enforcement of such requirement or law
                  is stayed during such contest and such contest will not
                  subject the Landlord to penalty or jeopardize the title to the
                  Premises or otherwise affect the Premises in any adverse way.
                  Landlord shall cooperate with Tenant in such contest and shall
                  execute any documents reasonably required in the furtherance
                  of such purpose. During the last three (3) years of the Term,
                  as it may be extended, any capital items in the Base Building
                  required to be installed by Tenant in the Premises after the
                  Term Commencement Date as hereinabove provided, having a
                  useful life greater than the remaining Term of the Lease shall
                  be paid for by Tenant in an amount equal to the cost of such
                  capital item multiplied by a fraction, the numerator of which
                  shall be equal to the number of months remaining in the
                  balance of the Term (including any exercised Extension
                  Options) and the denominator equal to the number of months of
                  the useful life of such capital item. Should Tenant later
                  extend the Term of this Lease, then on the first day of any
                  such Extension Term, Tenant shall pay as additional rent, an
                  additional reimbursement toward the cost of such previously
                  replaced capita item equal to the cost of such replaced item
                  multiplied by a fraction, the numerator of which equal the
                  number of months in the Extension Term, and the denominator
                  equal to the remaining useful life of said replaced item as
                  originally estimated hereunder. Whenever the fraction is equal
                  to or greater than one, then the fractional value shall be
                  equal to one (1). Notwithstanding the foregoing or any other
                  provision of this Lease, however, Tenant shall not be
                  responsible for compliance with any such laws, regulations, or
                  the like requiring (i) structural repairs or modifications or
                  (ii) repairs or modifications to the utility or building
                  service equipment located outside of and not exclusively
                  serving the Premises;

         6.1.6    Assignment and Subletting - Tenant shall have the right,
                  subject to the requirement of obtaining Landlord's prior
                  written consent, such consent not to be unreasonably withheld
                  or delayed by Landlord, to assign this Lease or sublet the
                  whole or any


                                       30

<PAGE>   35


                  portion of the Premises, which assignment or sublease shall be
                  only for the Permitted Uses, it being understood that Tenant
                  shall, as additional rent, reimburse Landlord promptly for
                  reasonable legal and other expenses incurred by Landlord in
                  connection with any request by Tenant for consent to
                  assignment or subletting. No assignment or subletting shall
                  affect the continuing primary liability of Tenant (which,
                  following assignment, shall be joint and several with the
                  assignee). Such consent by Landlord to any of the foregoing in
                  a specific instance (i) shall be reasonable, subject to the
                  provisions hereinafter provided, and (ii) shall be subject to
                  the prior written approval of Landlord's mortgagee(s).
                  Landlord's consent shall not be treated as having been
                  withheld unreasonably if, in connection with any such proposed
                  assignment or subletting: (i) the terms of the proposed
                  assignment or subletting do not prohibit further assignments
                  of the Lease or subletting of the Premises without the written
                  consent of Landlord, the granting of which consent shall be
                  subject to the terms and conditions hereof, and in any event
                  shall not be unreasonably withheld or delayed; and/or (ii) in
                  connection with an assignment of this Lease, the assignee does
                  not agree directly with Landlord, by written instrument in
                  form satisfactory to Landlord, to be bound by all the
                  obligations of Tenant hereunder including, without limitation,
                  the covenant against further assignment and subletting without
                  the written consent of Landlord; and/or (iii) the proposed
                  assignment or subletting violates an exclusive use restriction
                  of the Building or Park. Tenant hereby acknowledges and agrees
                  that the foregoing is not intended to be an exclusive list of
                  the reasons for which Landlord may reasonably withhold consent
                  to a proposed request by Tenant for consent to assignment or
                  subletting. No consent to any of the foregoing in a specific
                  instance shall operate as waiver in any subsequent instance.
                  In addition, Tenant shall not have the right to transfer or
                  convey to any sublessee(s) other than to a Permitted
                  Transferee (as defined below), any renewal, expansion, or
                  first refusal rights of Tenant set forth in this Lease.

                  If an assignment or subletting is proposed to be made and
                  Landlord's consent is required as hereinabove provided, Tenant
                  shall give Landlord prior notice of such proposal, which such
                  notice shall include such information as Landlord may
                  reasonably request relative to facts which would bear upon the
                  factors entering into the determination whether Landlord's
                  approval is to be granted, and it is understood that Landlord
                  shall use diligent efforts within a period of thirty (30) days
                  after the submission of such information by Tenant to make its
                  determination whether Landlord's approval is to be granted
                  hereunder.

                  Notwithstanding any provision contained in this Lease, no
                  consent of Landlord shall be required for the assignment of
                  this Lease or the subletting of any portion (or all) of the
                  Premises for the Permitted Uses, (i) to a subsidiary of
                  Tenant, (ii) to a corporation or other entity into or with
                  which Tenant has merged or consolidated or to which
                  substantially all of Tenant's stock or assets are transferred,
                  (iii) to any corporation or other entity which controls, is
                  controlled by, or is under common control with Tenant, or (iv)
                  to any corporation or other entity with which Tenant is


                                       31

<PAGE>   36


                  otherwise affiliated (collectively, the "Permitted
                  Transferees"); provided that, in any of such events, (x)
                  Tenant shall remain directly and primarily liable, and (y) any
                  such sublessee or assignee agrees directly with Landlord by
                  written instrument reasonably satisfactory to Landlord and
                  such assignee or sublessee to be bound by all of the
                  obligations of Tenant. In the event of any such assignment or
                  subletting for which no consent by Landlord is required
                  hereunder, Tenant shall not be obligated to share Rent
                  Differential as hereinafter set forth.

                  If this Lease shall be assigned, or if the Premises or any
                  part hereof shall be sublet or occupied by any person other
                  than Tenant, Landlord may, at any time and from time to time,
                  collect rent from the assignee, subtenant or occupant and
                  apply the net amount collected to the annual Fixed Rent,
                  additional rent and all other charges herein reserved, but no
                  such assignment, subletting, occupancy or collection shall be
                  deemed a waiver of the provisions of this Section 6.1.6, or
                  acceptance of the assignee, subtenant or occupant as tenant,
                  or a release of Tenant from the further performance of the
                  terms, covenants and conditions of this Lease on the part of
                  Tenant to be performed. Further, no liability hereunder of
                  Tenant shall be discharged, reduced, released or impaired in
                  any respect by any waiver, indulgence or extension of time
                  which Landlord may grant to the then owner of Tenant's
                  interest in this Lease, whether or not notice thereof has been
                  given or consent from Tenant has been obtained.

                  Landlord shall have the option to require that any portion of
                  rental received by Tenant from subtenant or assignee to which
                  Landlord is entitled pursuant to this Section 6.1.6 be
                  remitted directly to Landlord, provided that such amounts are
                  credited pro tanto against Tenant's rental obligations.

                  If Landlord approves a sublease or assignment, and said
                  sublease or assignment is for a total rental amount which on
                  an annualized basis is greater than the unreduced Fixed Rent
                  plus three dollars and sixty three cents ($3.63) per square
                  foot (as set forth in Section 3.8 of this Lease) and
                  additional rent due from Tenant to Landlord under this Lease,
                  Tenant shall pay to Landlord, forthwith upon Tenant's receipt
                  of each installment of such excess rent, during the term of
                  any approved sublease or assignment, as additional rent
                  hereunder, in addition to the Fixed Rent and other payments
                  due under this Lease, an amount equal to fifty percent (50%)
                  of the positive excess between all fixed rent and additional
                  rent received by Tenant under the sublease or assignment and
                  the unreduced Fixed Rent (as set forth in Section 3.8 of this
                  Lease) plus three dollars and sixty three cents ($3.63) per
                  square foot and the additional rent due hereunder after Tenant
                  has recouped its reasonable out-of-pocket expenses with
                  respect to such sublease or assignment, including without
                  limitation, reasonable real estate brokerage commissions,
                  reasonable legal fees, reasonable free rent, reasonable
                  marketing costs and the reasonable costs of refurbishment of
                  the Premises for such sublease or assignment (the "Rent
                  Differential"). The fifty percent (50%) figure set forth in
                  the immediately preceding sentence shall apply unless and
                  until the Tenant has


                                       32

<PAGE>   37


                  sublet or assigned fifty percent (50%) of the Premises; after
                  the time in which Tenant subleases more than fifty percent
                  (50%) of the Premises the percentage payable to the Landlord
                  as hereinabove provided shall increase on all sublease(s) and
                  any assignment to equal the percentage of the Premises being
                  subleased or assigned (by way of example and not limitation if
                  Tenant subleased seventy-five percent (75%) of the Premises,
                  Landlord would be entitled to seventy-five percent (75%) in
                  the calculation of the Rent Differential set forth above). In
                  the event the sublease is for less than the full Premises
                  hereunder, the above rent adjustment shall be equitably pro
                  rated on a square foot basis. Anything contained in the
                  foregoing provisions of this section to the contrary
                  notwithstanding, neither Tenant nor any other person having
                  interest in the possession, use, occupancy or utilization of
                  the Premises shall enter into any lease, sublease, license,
                  concession or other agreement for use, occupancy or
                  utilization of space in the Premises which provides for rental
                  or other payment for such use, occupancy or utilization based,
                  in whole or primarily on the net income or profits derived by
                  any person from the Premises leased, used, occupied or
                  utilized (other than an amount based on a fixed percentage or
                  percentages of receipts or sales), and any such purported
                  lease, sublease, license, concession or other agreement shall
                  be absolutely void and ineffective as a conveyance of any
                  right or interest in the possession use, occupancy or
                  utilization of any part of the Premises;

         6.1.7    Indemnity - To defend, with counsel reasonably acceptable to
                  Landlord, save harmless, and indemnify Landlord from any
                  liability for injury, loss, accident or damage to any person
                  or property occurring on the Premises, in the Building, or
                  elsewhere in the Park, and from any claims, actions,
                  proceedings and expenses and costs in connection therewith or
                  elsewhere in the Park (including, without implied limitation,
                  reasonable counsel fees): (i) arising from the negligent acts
                  or gross misconduct of Tenant or any of Tenant's employees,
                  agents, contractors, licensees or invitees and not caused
                  directly by the negligent acts or gross misconduct of
                  Landlord, or (ii) resulting from the failure of Tenant to
                  perform and discharge its covenants and obligations under this
                  Lease. In no event shall Tenant be obligated to indemnify
                  Landlord for any willful or negligent act or omission of
                  Landlord or any of Landlord's employees, agents, contractors
                  or licensees. The covenants and indemnifications set forth in
                  this Section 6.1.7 shall survive the expiration or earlier
                  termination of this Lease;

         6.1.8    Tenant's Liability Insurance - To maintain public liability
                  insurance in the Premises in amounts which shall, at the
                  beginning of the Term, be at least equal to the limits set
                  forth in Section 1.1 and from time to time during the Term,
                  shall be for such higher limits, if any, as are customarily
                  carried in the area in which the Premises are located on
                  property similar to the Premises and used for similar purposes
                  and, upon written request therefor, to furnish Landlord
                  (and/or its mortgagees) with certificates thereof;


                                       33

<PAGE>   38


         6.1.9    Tenant's Workers' Compensation Insurance - To keep all
                  Tenant's employees working in the Premises covered by workers'
                  compensation insurance in statutory amounts and to furnish
                  Landlord with certificates thereof;

         6.1.10   Landlord's Right of Entry - Signs and Flags - Upon not less
                  than twenty-four (24) hours advance notice (except in the
                  event of emergencies), to permit Landlord and Landlord's
                  agents entry; to examine the Premises at reasonable times and,
                  if Landlord shall so elect, to make repairs or replacements;
                  to remove, at Tenant's expense, any changes, additions, signs,
                  curtains, blinds, shades, awnings, aerials, flagpoles, or
                  other improvements visible outside the Building not consented
                  to in writing; Landlord acknowledging and agreeing however
                  that Tenant shall have the right, subject to Tenant obtaining
                  all necessary governmental permits and approvals, to install
                  and maintain three flag poles as well as one placard monument
                  sign with Tenant's logo, the latter only if permitted as of
                  right by the Town of Bedford, Massachusetts Bylaws, to be
                  located in front of the Building, outside of the Building
                  Parking Area and mutually acceptable to Landlord and Tenant.
                  Tenant shall reimburse Landlord for the actual third party
                  costs and expenses incurred by Landlord in connection with
                  obtaining said permits and approvals, including reasonable
                  attorney fees and disbursements; Tenant agrees to cooperate
                  with Landlord during the permitting process by (i) promptly
                  executing the necessary documentation requested by Landlord,
                  and (ii) by furnishing the same to Landlord promptly upon
                  Landlord's request, but in no event later than seven (7) days
                  following Landlord's request. Further the construction,
                  erection and maintenance of such flag poles and such placard
                  monument signage shall be the Tenant's sole responsibility and
                  at Tenant's sole cost and expense; and to show the Premises to
                  prospective tenants during the twelve (12) months preceding
                  expiration of the Term and to prospective purchasers and
                  mortgagees at all reasonable times;

         6.1.11   Loading - Not to place a load upon the Premises exceeding an
                  average rate of one hundred (100) pounds of live load per
                  square foot of floor area; and not to move any safe, vault or
                  other heavy equipment in, about or out of the Premises except
                  in such a manner and at such times as Landlord shall in each
                  instance approve; Tenant's business machines and mechanical
                  equipment which cause vibration or noise that may be
                  transmitted to the Building structure shall be placed and
                  maintained by Tenant in settings of cork, rubber, spring, or
                  other types of vibration eliminators sufficient to eliminate
                  such vibration or noise;

         6.1.12   Landlord's Costs - In case Landlord shall, without any fault
                  on its part, be made party to any litigation commenced by or
                  against Tenant or by any party claiming under Tenant, to pay,
                  as additional rent, all actual third party reasonable costs
                  including, without implied limitation, reasonable counsel fees
                  incurred by or imposed upon Landlord in connection with such
                  litigation, and, as additional rent, also to pay all such
                  reasonable costs and fees incurred by Landlord in connection


                                       34

<PAGE>   39

                  with the successful enforcement by Landlord of any obligations
                  of Tenant under this Lease;

         6.1.13   Tenant's Property - All the furnishings, fixtures, equipment,
                  effects and property of every kind, nature and description of
                  Tenant and of all persons claiming by, through or under Tenant
                  which, during the continuance of this Lease or any occupancy
                  of the Premises by Tenant or anyone claiming under Tenant, may
                  be on the Premises or on the Lot shall be at the sole risk and
                  hazard of Tenant, except for Landlord's gross negligence or
                  willful act or omission, and if the whole or any part thereof
                  shall be destroyed or damaged by fire, water or otherwise, or
                  by the leakage or bursting of water pipes, steam pipes, or
                  other pipes, by theft, or from any other cause, no part of
                  said loss or damage is to be charged to or to be borne by
                  Landlord, except if caused directly by Landlord's gross
                  negligence or willful misconduct;

         6.1.14   Labor or Materialmen's Liens - To pay promptly when due the
                  entire cost of any work done on the Premises by Tenant, its
                  agents, employees, or independent contractors; not to cause or
                  permit any liens for labor or material performed or furnished
                  in connection therewith to attach to the Premises; and within
                  ten (10) days after Tenant's receipt of notice thereof, to
                  discharge or bond over with a bond satisfactory to Landlord
                  and Landlord's mortgagee(s) any such liens which may so
                  attach;

         6.1.15   Changes or Additions - Not to make any material changes or
                  additions to the Premises without Landlord's prior written
                  consent, which such consent shall not be unreasonably withheld
                  or delayed. Notwithstanding the foregoing, Tenant may, from
                  time to time, at its own cost and expense and without the
                  consent of Landlord, make non-structural alterations,
                  additions or improvements to the Premises, so long as they do
                  not affect any of the mechanical, electrical or plumbing
                  systems of the Building (collectively herein called
                  "Alterations") whose cost in any one instance is Fifty
                  Thousand Dollars ($50,000.00) or less, provided that Tenant
                  first notifies Landlord in writing of any such Alterations. If
                  Tenant desires to make any Alterations costing in excess of
                  Fifty Thousand Dollars ($50,000.00) in any one instance or any
                  other alteration, including any structural alteration or
                  alteration affecting any of the mechanical, electrical or
                  plumbing systems of the Building, Tenant must first obtain the
                  consent of Landlord thereto, which consent shall not be
                  unreasonably withheld or delayed. If Landlord reasonably
                  concludes that the Alterations involve any construction,
                  alterations or additions requiring unusual expense to readapt
                  the Premises to normal office use on the Term Expiration Date,
                  Landlord shall notify Tenant in writing at the time of
                  approval that such readaptation will be required to be made by
                  Tenant prior to such Term Expiration Date without expense to
                  Landlord.

                  Any and all such alterations, including Alterations, may be
                  done by any contractor chosen by Tenant provided any such
                  contractor is reputable, bondable by


                                       35
<PAGE>   40


                  reputable bonding companies, carries the kind of insurance and
                  in the amounts set forth herein, and will work in harmony with
                  Landlord's contractors and laborers in the Building;

                  Tenant shall ensure that its contractors and subcontractors
                  procure and maintain insurance as required by Tenant's
                  Contractors and Subcontractors Minimum Insurance Requirements
                  set forth in Exhibit "H" of this Lease.

                  Tenant in making any alterations, including Alterations, shall
                  cause all work to be done in a good and workmanlike manner
                  using materials substantially equal to or better than those
                  used in the construction of the Premises or original Tenant's
                  Work and shall comply with or cause compliance with all laws
                  and with any direction given by any public officer pursuant to
                  law. Tenant shall obtain or cause to be obtained and maintain
                  in effect, as necessary, all building permits, licenses,
                  temporary and permanent certificates of occupancy and other
                  governmental approvals which may be required in connection
                  with the making of the alterations, including the Alterations.
                  Landlord shall cooperate with Tenant in the obtaining such
                  permits, licenses and approvals and shall execute any
                  documents reasonably required in furtherance of such purpose,
                  provided any such cooperation shall be without expense and/or
                  liability to Landlord.

                  At least annually if such Alterations or any other alterations
                  hereunder have occurred during the past calendar year, Tenant
                  shall furnish to Landlord as-built sepias and, if applicable,
                  operating manuals, or, at Landlord's option and only if
                  Tenant's computer system is compatible with that of
                  Landlord's, computer disk specifications compatible with
                  Landlord's computer system of the work done by Tenant during
                  such past year and copies of all permits issued in connection
                  therewith.

                  Tenant shall have its contractor procure and maintain in
                  effect during the term of such alterations, including
                  Alterations, satisfactory insurance coverages with an
                  insurance company or companies authorized to do business in
                  the Commonwealth of Massachusetts, and shall, upon Landlord's
                  request, furnish Landlord with certificates thereof;

         6.1.16   Holdover - To pay to Landlord two hundred percent (200%) the
                  total of the Fixed and additional rent then applicable for
                  each month or portion thereof Tenant shall retain possession
                  of the Premises or any part thereof after the termination of
                  this Lease, whether by lapse of time or otherwise; provided
                  however that Tenant shall be responsible to pay to Landlord
                  only one hundred twenty-five (125%) percent of the total Fixed
                  Rent and additional rent then applicable for the first (60)
                  sixty days Tenant retains possession of the Premises or any
                  part thereof after termination of this Lease. The provisions
                  of this subsection shall not operate as a waiver by Landlord
                  of any right of re-entry provided in this Lease;


                                       36
<PAGE>   41


         6.1.17   Hazardous Materials - Tenant shall not (either with or without
                  negligence) cause or permit the escape, disposal or release of
                  any biologically or chemically active or other hazardous
                  substances or materials onto the Premises or the Lot, except
                  in accordance with the requirements of applicable laws and
                  regulations. Tenant shall not allow the storage or use of such
                  substances or materials in any manner not permitted by law,
                  nor allow to be brought into the Premises any such materials
                  or substances except to use in the ordinary course of Tenant's
                  business. Upon Landlord's written request, Tenant shall
                  furnish to Landlord an inventory of the identity of such
                  substances or materials used in the ordinary course of
                  Tenant's business. Without limitation, hazardous substances
                  and materials shall include those described in the
                  Comprehensive Environmental Response, Compensation and
                  Liability Act of 1980, as amended, 42 U.S.C. Section 9601 et
                  seq., the Resource Conservation and Recovery Act, as amended,
                  42 U.S.C. Section 6901 et seq., the Massachusetts Hazardous
                  Waste Management Act, as amended, M.G.L. c.21C, the
                  Massachusetts Oil and Hazardous Material Release Prevention
                  and Response Act, as amended, M.G.L. c.21E, any applicable
                  local ordinance or bylaw, and the regulations adopted under
                  these acts, as amended (collectively, the "Hazardous Waste
                  Laws"). If any lender or governmental agency shall ever
                  require testing to ascertain whether or not there has been any
                  release of hazardous substances or materials, then the
                  reasonable costs thereof shall be reimbursed by Tenant to
                  Landlord upon demand as additional charges if and only if the
                  following conditions are satisfied; (i) if such requirement
                  applies to the Premises and (ii) if an independent, reputable
                  third party engineer employed by Landlord or persons acting
                  under Landlord conclusively determines that such release had
                  been or is likely to have been solely and exclusively caused
                  by Tenant or persons acting under Tenant. If Tenant receives
                  from any federal, state or local governmental agency any
                  notice of violation or alleged violation of any Hazardous
                  Waste Law, or if Tenant is obligated to give any notice under
                  any Hazardous Waste Law, Tenant agrees to forward to Landlord
                  a copy of any such notice within three (3) days of Tenant's
                  receipt or transmittal thereof. In addition, Tenant shall
                  execute affidavits, representations and the like from time to
                  time at Landlord's request concerning Tenant's best knowledge
                  or belief regarding the presence of hazardous substances or
                  materials on the Premises. In all events, Tenant shall
                  indemnify Landlord in the manner provided in Section 6.1.7 of
                  this Lease from any release of hazardous substances or
                  materials on the Premises or elsewhere in the Park to the
                  extent caused by Tenant or persons acting under Tenant.
                  Notwithstanding the immediately preceding sentence, after
                  deducting all of Landlord's costs, if any, Landlord will
                  credit Tenant with any net insurance proceeds received by
                  Landlord from any Pollution and Remediation Legal Liability
                  insurance policy in effect covering the Premises. Landlord
                  retains the right to inspect the Premises at all reasonable
                  times, upon reasonable notice to Tenant, to ensure compliance
                  with this Section. The within covenants shall survive the
                  expiration or earlier termination of the Term;


                                       37

<PAGE>   42


         6.1.18   Signs - Tenant shall not, without prior written consent of
                  Landlord (which such consent shall not be unreasonably
                  withheld or denied but may be withheld in Landlord's sole
                  discretion if Tenant is then in default of this Lease beyond
                  any applicable cure periods or if Tenant is not then leasing
                  at least seventy-five percent (75%) of the Building) (for
                  purposes of this 75% determination, space subleased to others
                  by Tenant will not be deducted from Tenant's Leased Premises),
                  (a) place any exterior signs visible outside the Building, on
                  the Lot or the Premises or anywhere on the exterior of the
                  Building, or (b) place any curtains, blinds (other than
                  standard vertical blinds), shades, awnings, or flagpoles, or
                  the like, in the Premises or anywhere on or in the Building
                  visible from outside the Premises, except as otherwise
                  expressly set forth below in this Section 6.1.18 or elsewhere
                  in this Lease. Tenant shall pay the expenses involved in the
                  erection of any sign and of obtaining all necessary permits
                  and approvals therefor. Except as otherwise provided below
                  with respect to the initial Building signage, Tenant warrants
                  that it shall obtain (and furnish copies thereof to Landlord)
                  all necessary permits and approvals in compliance with local
                  codes and ordinances prior to erecting any such sign(s) and
                  that all of such signage shall be in accordance with
                  first-class building standards. Tenant shall remove any of
                  such sign(s) erected by Tenant or on behalf of Tenant upon the
                  termination of this Lease.

                  In connection with Tenant's initial Building signage, Landlord
                  shall use reasonable efforts to obtain, on Tenant's behalf,
                  all necessary permits and approvals required pursuant to local
                  codes and ordinances for the building and site signage (i.e.,
                  two signs on the Building facade, signage on the entrance sign
                  of the Park, and signage on the Building' directory and on any
                  other applicable floor directories of the Building) set forth
                  and described in Exhibit H hereto. Tenant's Building and Lot
                  signage shall be exclusive until such time as Tenant fails to
                  lease at least seventy-five percent (75%) of the Building or
                  Tenant defaults in the terms of this Lease beyond applicable
                  cure periods. In addition thereto, provided Tenant is the sole
                  tenant in the Park, Tenant shall have the right, subject to
                  all applicable laws, ordinances and regulations and subject to
                  Tenant obtaining all necessary permits and approvals required
                  pursuant to all applicable laws to install and maintain one
                  placard monument sign at the entrance to the Park and one
                  monument sign immediately adjacent to the Building. If Tenant
                  is not the sole tenant in the Park then so long as Tenant is
                  leasing at least two (2) entire buildings in the Park, if
                  Tenant can obtain the required permits and approvals for two
                  (2) monument signs at the entrance to the Park, subject to
                  Tenant obtaining all necessary permits and approvals for both
                  such signs, then Tenant shall be entitled to install and
                  maintain one such sign, the choice of the two sign locations
                  to be the Landlord's. Tenant shall reimburse Landlord for the
                  actual third-party reasonable costs and expenses incurred by
                  Landlord in connection with obtaining said permits and
                  approvals, including reasonable attorneys fees and
                  disbursements. Tenant agrees to cooperate with Landlord during
                  the permitting process by (i) promptly executing the necessary
                  documentation reasonably requested by


                                       38

<PAGE>   43

                  Landlord, and (ii) by furnishing the same to Landlord promptly
                  upon Landlord's request, but in no event later than seven (7)
                  days following Landlord's request. Further, the construction,
                  erection and maintenance of any such signage shall be Tenant's
                  sole responsibility and at Tenant's sole cost and expense.
                  Notwithstanding the foregoing, Landlord and Tenant agree (i)
                  that the cost of the signage on the Building's directory and
                  on other applicable floor directories shall be borne by
                  Landlord, with the graphics cost/placement being the
                  responsibility of the Tenant, and (ii) that Tenant shall have
                  the right, at its sole cost, to place its corporate logo on
                  the entrance door to the Premises and elsewhere within the
                  Premises;

         6.1.19   LIGHTING RESTRICTIONS - Landlord is obliged under agreements
                  with the Town of Bedford, Massachusetts to ensure that all
                  interior lights in the Building (except for emergency lights)
                  that are on the northwest (front) side of the Building, or are
                  readily visible from the northwest side of the Building be
                  controlled by motion detector shut offs that will turn off
                  such lights in such spaces when motion is not detected
                  therein. Such switches will be installed in such Tenant Space.
                  Landlord shall reimburse Tenant the initial marginal cost of
                  installing such motion detector switches.

         6.1.20   TRANSPORTATION DEMAND MANAGEMENT PLAN - This property is
                  subject to a Special Permit from the Town of Bedford,
                  Massachusetts for increased number of parking spaces. The
                  Tenant agrees to cooperatively participate in, and actively
                  support, Landlord's and/or the Park's Transportation Demand
                  Management Plan wherever possible to achieve the Park's goal
                  of peak hour traffic reduction. Tenant shall reimburse
                  Landlord for its pro rata share of Landlord's Transportation
                  Demand Management Plan expenses which may include such
                  services as:

                    *    Access GIS/Rideshare to assist in matching interested
                         employees into car-pools and vanpools.

                    *    Provide a "Guaranteed Ride" program which provides a
                         back-up in the event of an emergency;

                    *    Promotional events at their facilities to distribute
                         transportation information and answer questions;

                    *    Operate a "transportation store" to provide up-to-date
                         information on transit schedules, services, and fares;

                    *    Organize van-pools;

                    *    Work with state agencies including MassHighway, EOTC,
                         CARAVAN Commuters, or others, as necessary on
                         transportation matters; and


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<PAGE>   44

                    *    Implement preferential parking for rideshares.

         6.1.21   TELECOMMUNICATIONS AND ROOFTOP INSTALLATIONS - Tenant is
                  hereby granted the right, subject to applicable law and the
                  last sentence of this Section 6.1.21 to use the roof of the
                  Building (the "Roof") for the installation, operation and
                  maintenance, at Tenant's sole cost and expense, of such
                  telecommunications equipment and devices thereon as Tenant
                  shall elect to install and operate in its reasonable
                  discretion (subject to the limitations in this Section 6.1.21.
                  Tenant's Rooftop Improvements shall not (a) have any material
                  adverse impact on the structural integrity of the Building or
                  roof, (b) void a roof membrane warranty or guaranty, or
                  materially and adversely disturb or otherwise affect the
                  architectural integrity of the Building, (c) be substantially
                  dissimilar from those generally installed on other similar
                  office and research and development buildings of which Tenant
                  is the owner or a substantial occupant, or (d) be used for
                  telecommunications services for the benefit of persons or
                  entities other than Tenant or any subtenant or assignee of
                  Tenant (it being agreed that the sale of telecommunications
                  services to members of the public is not included within the
                  rights granted to Tenant under this Section 6.1.21), but is
                  reserved to Landlord. Prior to the installation of any Rooftop
                  Improvements, Tenant shall obtain and submit to Landlord (x)
                  for its approval, plans and specifications for the proposed
                  Rooftop Improvements (including its size, location, height,
                  weight and function), along with copies of all required
                  permits and licenses required from all applicable governmental
                  authorities, and (y) if Tenant so elects, a request that
                  Landlord not require Tenant to remove the Rooftop Improvements
                  at the end of the Term. Such approval under clause (x) shall
                  be limited to determining only that Tenant has obtained all
                  required permits and licenses for the installation and
                  operation of the Rooftop Improvement(s), that the Rooftop
                  Improvement(s) comply with all applicable laws, and that
                  Tenant has satisfied the other conditions set forth in this
                  Section 6.1.21 and such decision regarding non-removal under
                  clause (y) shall be at Landlord's sole discretion. Should
                  Landlord, in its reasonable judgment, deem it necessary to
                  have Tenant's plans and specifications for Rooftop
                  Improvements reviewed by a structural engineer, Tenant shall
                  reimburse Landlord the reasonable cost of such review as
                  Additional Rent within sixty (60) days of billing therefore.
                  In the event this Lease is subsequently amended and Tenant is
                  no longer the sole tenant in the Building and a third-party is
                  also a tenant in the Building, Tenant's rights to use the roof
                  shall be proportionate to the portion of the Building then
                  leased by Tenant and Tenant agrees to abide by the following
                  terms and conditions: (1) Prior to the commencement of
                  installation of any Rooftop Improvement, Tenant shall have in
                  effect and shall deliver to Landlord evidence of the insurance
                  coverages required under this Lease and that such insurance
                  includes coverage of the Rooftop Improvement. Such insurance
                  shall name Landlord and each mortgagee of the Premises of
                  which Tenant has notice as an additional insured or loss
                  payee, as its interest may appear, where appropriate; (2) At
                  all times during the installation process, Tenant will exhibit
                  any required low voltage permit, building permit, and/or any
                  other permits to be issued. Tenant


                                       40
<PAGE>   45


                  hereby confirms that it shall at all times during the
                  installation or removal process or during any use, maintenance
                  and repair of any Rooftop Improvement, comply with all
                  building, safety, fire, plumbing, electrical and other codes
                  and governmental insurance requirements and roof warranty
                  requirements, as more fully set forth in the Lease; (3) As
                  soon as practicable during the installation of any Rooftop
                  Improvement, Tenant, at its sol cost and expense (i) will seal
                  any wall penetrations occurring by reason of the installation
                  process inside the ceiling plenum, and (ii) will have any roof
                  penetrations occurring by reason of the installation process
                  sealed by a roofing subcontractor selected by Tenant and
                  approved by Landlord; (4) Tenant agrees to indemnify, defend
                  and hold Landlord and any Landlord related party and each
                  mortgagee of the Premises and Landlord's contractors harmless
                  from any damage to any tangible property or bodily injury to,
                  or death of, any person arising from the installation,
                  maintenance, operation and continued use of the Rooftop
                  Improvements by Tenant or its agents, assignees, subtenants,
                  employees, representatives, contractors or invitees; (5)
                  Tenant shall keep the Premises, the Building and the Rooftop
                  Improvements free and clear of any liens arising from any work
                  performed, materials furnished or obligations incurred by or
                  at the request of Tenant, its agents, employees or independent
                  contractors and (6) Tenant shall keep the Rooftop
                  Improvements, and every part thereof, in good condition and
                  repair at all times during the Term and at Tenant's sole cost
                  and expense.

         Unless Landlord has previously approved Tenant's non-removal of the
Rooftop Improvements at the end of the term pursuant to Section 6.1.21 B, Tenant
shall remove all Rooftop Improvements at the expiration of the Term and restore
the area where the Rooftop Improvements were located to its original condition,
at Tenant's sole expense; all such removal of Rooftop Improvements shall be done
in a manner that will not have any material adverse impact on the structural
integrity of the Building or Roof and will not void a Roof membrane warranty or
guaranty.

         6.1.22   Tenant's Authority - Tenant has the power and authority to
                  enter into this Lease and perform the obligations of Tenant
                  hereunder. This Lease and all other documents executed and
                  delivered by Tenant in connection herewith constitute legal,
                  valid, binding and enforceable obligations of Tenant; and

         6.1.23   Confidentiality - This Lease document is a confidential
                  document by and between Landlord and Tenant and Tenant agrees
                  that this Lease shall not be copied and distributed or
                  circulated to any person(s) other than to such parties, and
                  their respective mortgagees, successors or assigns, their
                  legal counsel or their accountants or to any prospective
                  sublessees and assignees or affiliates of Tenant, or to any
                  prospective acquirers, investors, or lenders of Tenant, or to
                  regulatory authorities, or to the directors, shareholders or
                  officers of Tenant, or as required by law, without the prior
                  written consent of Landlord. Nothing contained in this Section
                  shall prohibit the disclosure by Tenant of the essential terms
                  of this Lease.


                                       41
<PAGE>   46

                                   ARTICLE VII
                               CASUALTY AND TAKING

7.1      CASUALTY AND TAKING

         In case during the Term all or any substantial part of the Premises,
and/or the Building Parking Area, or any part thereof, or both (i.e. in the case
of a fire or casualty, requiring greater than twelve (12) months to rebuild in
Landlord's reasonable judgment; or in the case of a condemnation or a taking,
more than thirty-five percent (35%) of the floor area of the Premises or any
material part of the means of access thereto or more than twenty-five percent
(25%) of Building Parking Area) are damaged by fire or any other casualty or by
action of public or other authority in consequence thereof or are taken by
eminent domain Landlord shall give prompt notice, (i.e. within thirty (30) days
thereof) to Tenant (the "Landlord's Notice") and this Lease shall terminate
either at Landlord's or Tenant's election, which may be made by notice given to
the other within thirty (30) days after the date of Landlord's Notice, which
termination shall be effective (i) in the event of a casualty, not less than
thirty (30) nor more than sixty (60) days after the date of notice of such
termination and (ii) in the event of eminent domain event, as of the date on
which such taking becomes effective and Tenant is deprived of the use and
enjoyment of the Premises, or part thereof, and/or the Building Parking Area, or
part thereof. In the event Landlord elects not to rebuild, then any insurance
proceeds actually received by Landlord shall, during the initial Term, be
allocated between Landlord and Tenant as follows: first, to Landlord's
mortgagee(s) up to the amount of the mortgage(s) then, to the Tenant an amount
equal to the sum of the amounts actually paid by Tenant to Landlord for the
Tenant's Work installed hereunder multiplied by a fraction the numerator of
which is the number of months remaining in the initial Term and denominator of
which is one hundred and eighty (180), plus the total amount of the Tenant's
Contribution to Landlord's Work multiplied by a fraction the numerator of which
is the number of months remaining in the initial Term plus (one hundred twenty
(120) months less any expired months in any extended terms) and denominator of
which is three hundred (300); then to Landlord or its mortgagee(s), as their
interests may appear, that certain portion of any remaining insurance proceeds.
Notwithstanding any language to the contrary, any and all of Landlord's
obligations to allocate to Tenant any such portion of the insurance proceeds
described in the preceding sentence shall be limited to the extent such proceeds
are actually received by Landlord.If in any such case the Lease is not so
terminated, Landlord shall proceed promptly and use due diligence to put the
Premises, or part thereof, and/or the Building Parking Area, or part thereof, or
in case of taking, what may remain thereof (excluding any items installed by
Tenant which Tenant may be permitted to remove upon the expiration of the Term)
into as near as possible to the condition and character thereof prior to such
damage or taking, and in any event shall apply all insurance proceeds or eminent
domain awards received by it toward such work, for use and occupation to the
extent permitted by the net award of insurance plus any deductibles and such
amounts as Tenant may elect to make available for such work as hereinafter
provided, or the amount of the eminent domain award, and an equitable proportion
of the Fixed Rent and additional rent according to the nature and extent of the
injury shall be abated until the Premises or such remainder and the Building
Parking Area shall have been put by Landlord in such condition; and in case of a
taking which permanently reduces the area of the Premises, an equitable
proportion of the Fixed Rent and additional rent shall be abated for the
remainder of the

                                       42

<PAGE>   47

Term and an appropriate adjustment shall be made to the Annual Estimated
Operating Costs and other additional rent payable hereunder.

         However, in the case of a casualty, if such damage is not repaired and
the Premises, or portion thereof, and/or Building Parking Area or part thereof,
restored to the same condition as they were prior to such damage within twelve
(12) months from the date of Landlord's Notice, then Tenant, within thirty (30)
days from the expiration of such twelve (12) month period or from the expiration
of any extension thereof by reason of any Tenant's Delay (as defined in Section
3.2 hereof) and/or Force Majeure (as defined in Section 3.5 hereof and subject
to the provisions set forth below) as hereinafter provided, may terminate this
Lease by notice to Landlord and Landlord's mortgagee(s), given in accordance
with Section 10.3 hereof, specifying a date not more than thirty (30) days after
the giving of such notice on which the Term of this Lease shall terminate.
Notwithstanding such termination notice by Tenant, in the event that Landlord
repairs such damage and restores the Premises to the same condition prior to
such casualty during such period, not to exceed thirty (30) days, as specified
in Tenant's notice, then such notice of termination given by Tenant to Landlord
hereunder shall be null and void and of no further force or effect. The period
within which the required repairs may be accomplished hereunder shall be
extended by (a) the number of days lost as a result of a Tenant's Delay, as
defined in and subject to the provisions of Section 3.2, with such term,
however, relating to restoration or repair as referenced herein and not to the
initial construction of the Building, and (b) the number of days lost as a
result of Force Majeure, as defined in Section 3.5.

         If less than a substantial part of the Premises or Lot, or portion
thereof, and/or the Building Parking Area, or portion thereof (i.e. in the case
of a fire or casualty, requiring less than twelve (12) months to rebuild in
Landlord's reasonable judgment; or in the case of a condemnation or taking
thirty-five percent (35%) or less of the floor area of the Premises or any part
of the means of access thereto or twenty-five percent (25%) or less of the
Building Parking Area) are damaged by fire or any other casualty or are taken by
eminent domain, then Landlord shall give prompt notice (i.e. within thirty (30)
days) thereof to Tenant, which notice shall specify Landlord's estimation of the
time period within which such repairs shall be completed, and thereafter
Landlord shall proceed promptly and with due diligence to repair such damage and
restore the Premises to the extent permitted by the net award of insurance plus
any deductible amounts and such amount as Tenant may elect to make available for
such work as hereinafter provided, or the amount of the eminent domain award. In
the event that Landlord fails to repair such damage and restore the Premises to
substantially the same condition that existed prior to such fire or other
casualty within the time period as reasonably estimated by Landlord, plus sixty
(60) days but in no event greater than such twelve (12) month period from the
date of such Landlord's notice to Tenant, or any extension thereof permitted for
delays lost due to any Tenant's Delay and/or Force Majeure (as hereinbefore
provided), then Tenant may (i) terminate this Lease by written notice to
Landlord and to Landlord's mortgagee(s), as provided in Section 10.3 hereof,
specifying a date not more than thirty (30) days after the giving of such notice
on which the Term of this Lease shall terminate or (ii) after fifteen (15) days
written notice to Landlord, repair such damage itself, in which event, Landlord
shall pay to Tenant, after deducting Landlord's costs, if any, any net insurance
proceeds received by Landlord that are received for such casualty.
Notwithstanding such termination notice by Tenant, in the event that Landlord


                                       43

<PAGE>   48

repairs such damage and restores the Premises to substantially the same
condition prior to such fire or other casualty during such period, not to exceed
thirty (30) days, as specified in Tenant's notice, then such notice of
termination given by Tenant to Landlord hereunder shall be null and void and of
no further force and effect. If less than a substantial part of the Premises
and/or the Building Parking Area shall be so damaged, then Fixed Rent and
additional rent due hereunder shall be equitably abated until thirty (30) days
after the Premises and/or the Building Parking Area are so restored as set forth
hereunder.

         Landlord's architect's certificate, given in good faith, shall be
deemed conclusive statements therein contained and binding upon Tenant with
respect to the performance and completion of any repair or restoration work
undertaken by Landlord pursuant to this Section, except in the event of
disagreement between Landlord and Tenant relating to this Section, in which
event the dispute resolution provisions of Section 3.6 shall apply.

         Notwithstanding any language to the contrary, Landlord may construct
"Replacement Parking" pursuant to the following: If not more than thirty-five
percent (35%) of the Building Parking Area shall be so damaged, taken,
appropriated, or condemned as aforesaid, then Landlord may elect to provide
Replacement Parking and render Tenant's notice of termination nugatory (if
applicable) by, within thirty (30) days following the effective date of such
destruction, taking, appropriation or condemnation, giving to Tenant notice in
writing that Landlord will, at Landlord's expense, construct replacement parking
spaces of the same quantity and quality and convenience as the parking spaces so
taken, appropriated or condemned (i.e., Landlord using best efforts to locate
the replacement parking spaces as close to the Building as possible). Any of
such Replacement Parking shall be constructed by Landlord within a reasonable
time period following the effective date of such destruction, taking,
appropriation or condemnation, but in no event later than ninety (90) days after
the occurrence of such destruction, taking, appropriation or condemnation, it
being agreed by Landlord and Tenant that such time period shall be extended to
include weather-related delays as aforesaid, in which event such Replacement
Parking will be completed as reasonably possible thereafter, Landlord agreeing
to proceed promptly and with due diligence to complete construction of any
Replacement Parking. Landlord and Tenant acknowledge that if Landlord is
prevented from performing the final paving for said Replacement Parking on
account of weather, such final paving may be performed as soon thereafter as is
feasible. Such notice shall be accompanied by (A) a site plan showing (i) the
location of the Replacement Parking spaces, and (B) an opinion from counsel for
Landlord that such Replacement Parking may be constructed as-of-right under then
applicable zoning and land use regulations.

         In the event of any other taking of the Premises, or any part thereof,
for temporary use or for less than one (1) year, (i) this Lease shall be and
remain unaffected thereby; and (ii) Landlord shall pay to Tenant its pro rata
share of any such award, provided that if any taking is for a period extending
beyond the Term of this Lease, such award shall be appointed between Landlord
and Tenant as of the Term Expiration Date.

         Tenant has the option but not the obligation, in any fire or other
casualty which creates a Landlord repair obligation in accordance with the terms
of this Section to make available for


                                       44
<PAGE>   49


such reconstruction all or a portion of the amount by which the cost of repair
as certified by Landlord's architect exceeds the amount of proceeds received by
Landlord.

7.2      RESERVATION OF AWARD

         Landlord reserves to itself any and all rights to receive awards made
for damages to the Premises or Lot and the leasehold hereby created, or any one
or more of them, accruing by reason of exercise of eminent domain or by reason
of anything lawfully done in pursuance of public or other authority. Tenant
hereby releases and assigns to Landlord all Tenant's rights to such awards, and
covenants to deliver such further assignments and assurances thereof as Landlord
may from time to time request. It is agreed and understood, however, that
Landlord does not reserve to itself, and Tenant does not assign to Landlord, any
damages payable for (i) movable trade fixtures installed by Tenant or anybody
claiming under Tenant, at its own expense, or (ii) relocation expenses
recoverable by Tenant from such authority in a separate action, or (iii) the
value of Tenant's improvements installed in the Premises by or on behalf of
Tenant, but not by Landlord provided, however, if damages payable for (i) and
(ii) above are not awarded by such authority in a separate action, then Tenant
shall only be entitled to recover such damages if such authority expressly
provides that portion of the awards received allocable to (i) and (ii) above AND
if payment to Tenant of such damages does not otherwise reduce or limit
Landlord's award hereunder. Notwithstanding the foregoing, Landlord agrees that
the award from any such taking shall, during the initial Term, be allocated
between Landlord and Tenant as follows: first, to Landlord's mortgagee(s) up to
the amount of the mortgage(s) then, to the Tenant an amount equal to the sum of
the amounts actually paid by Tenant to Landlord for the Tenant's Work installed
hereunder multiplied by a fraction the numerator of which is the number of
months remaining in the initial Term and denominator of which is one hundred and
eighty (180) plus, the total amount of the Tenant's Contribution to Landlord's
Work multiplied by a fraction the numerator of which is the number of months
remaining in the initial Term plus (one hundred twenty (120) months less any
expired months in any Extended Terms) and denominator of which is three hundred
(300); then to Landlord or its mortgagee(s), as their interests may appear, that
certain portion of any remaining award. Notwithstanding any language to the
contrary, any and all of Landlord's obligations to allocate to Tenant any such
portion of the award described in the preceding sentence shall be limited to the
extent such proceeds are actually received by Landlord.

7.3      ADDITIONAL CASUALTY PROVISIONS

         (a) Landlord shall not be required to repair or replace any of Tenant's
business machinery, equipment, cabinet work, furniture, personal property or
other installations not originally installed by Landlord.

         (b) In the event of any termination of this Lease pursuant to this
Article VII, the Term of this Lease shall expire as of the effective termination
date as fully and completely as if such date were the date herein originally
scheduled as the Term Expiration Date, and Landlord shall assist Tenant to the
extent necessary to secure Tenant's share of any insurance award relative to the
Tenant's Work hereunder. Tenant shall have access to the Premises at Tenant's
sole risk for a

                                       45

<PAGE>   50


period of thirty (30) days after the date of termination in order to remove
Tenant's personal property except as prohibited by any applicable governmental
agency or official.

         (c) Notwithstanding any language to the contrary contained in this
Article VII, if all or any substantial part of the Premises and/or the Building
Parking Areas or any part thereof (as hereinabove defined), shall be damaged by
fire or other casualty or taken by eminent domain during the last two (2) years
of the Term of this Lease or the last two (2) years of either of the Extended
Terms, as the case may be, then either Landlord or Tenant may terminate this
Lease effective as of the date of such fire or other casualty or taking upon
notice to the other as aforesaid, except that Tenant may render Landlord's
notice of termination nugatory by exercising early its option to extend the
initial Term, or the applicable Extended Term, as the case may be, of this Lease
for five (5) additional years in accordance with Exhibit F. In the event of such
early exercise, Landlord and Tenant agree to determine the Fixed Rent for the
applicable Extended Term at least nine (9) months prior to the commencement date
of the applicable Extended Term in accordance with and in the manner set forth
in said Exhibit F.

                                  ARTICLE VIII
                               RIGHTS OF MORTGAGEE

8.1      PRIORITY OF LEASE

         Landlord shall have the option to subordinate this Lease to any
mortgagee or deed of trust of the Lot or Premises, or both ("the mortgaged
premises"), provided that the holder thereof enters into a Subordination,
Non-Disturbance and Attornment Agreement substantially in the form attached
hereto as Exhibit J (or such other form mutually agreeable to Landlord, Tenant
and Landlord's mortgagee, each party agreeing to reasonably cooperate with each
other in reaching mutual agreement on the content of any such other form).

8.2      LIMITATION ON MORTGAGEE'S LIABILITY

         Upon entry and taking possession of the mortgaged premises for any
purpose other than foreclosure, the holder of a mortgage shall have all rights
of Landlord, and during the period of such possession, the duty to perform all
Landlord's obligations hereunder. Except during such period of possession, no
such holder shall be liable, either as mortgagee or as holder of a collateral
assignment of this Lease, to perform, or be liable in damages for failure to
perform any of the obligations of Landlord unless and until such holder shall
enter and take possession of the mortgaged premises for the purpose of
foreclosing a mortgage. Upon entry for the purpose of foreclosing a mortgage,
such holder shall be liable to perform all of the obligations of Landlord,
subject to the provisions of Section 8.3 provided that a discontinuance of any
foreclosure proceeding shall be deemed a conveyance under the provisions of
Section 10.4 to the owner of the equity of the mortgaged premises. From and
after making entry and taking possession of the Premises, any such mortgagee
shall be fully and completely liable for the obligations hereunder.


                                       46
<PAGE>   51


8.3      MORTGAGEE'S ELECTION

         Notwithstanding any other provision to the contrary contained in this
Lease, if prior to the substantial completion of Landlord's obligations under
Article III, any holder of a first mortgage on the mortgaged premises enters and
takes possession thereof for the purpose of foreclosing the mortgage, such
holder may elect, by written notice given to Tenant and Landlord at any time
within thirty (30) days after such entry and taking of possession, not to
perform Landlord's obligations under Article III, and in such event such holder
and all persons claiming under it shall be relieved of all obligations to
perform, and all liability for failure to perform, said Landlord's obligations
under Article III, and Tenant may terminate this Lease and all its obligations
hereunder by written notice to Landlord and such holder given within thirty (30)
days after the day on which such holder shall have given its notice as
aforesaid.

8.4      NO PREPAYMENT OR MODIFICATION, ETC.

         No Fixed Rent, additional rent, or any other charge shall be paid more
than thirty (30) days prior to the due dates thereof, and payments made in
violation of this provision shall (except to the extent that such payments are
actually received by a mortgagee in possession or in the process of foreclosing
its mortgage) be a nullity as against such mortgagee. No assignment of this
Lease (excepting only in accordance with the provisions of this Lease) and no
agreement to make or accept any surrender, termination or cancellation of this
Lease (excepting only in accordance with the provisions of this Lease) and no
agreement to modify so as to reduce the rent, change the Term, or otherwise
materially change the rights of Landlord under this Lease, or to relieve Tenant
of any obligations or liability under this Lease, shall be valid unless
consented to in writing by Landlord's mortgagees of which Tenant has received
notice.

8.5      NO RELEASE OR TERMINATION

         No act or failure to act on the part of Landlord which would entitle
Tenant under the terms of this Lease, or by law, to be relieved of Tenant's
obligations hereunder or to terminate this Lease, shall result in a release or
termination of such obligations or a termination of this Lease unless (i) Tenant
shall have first given thirty (30) days prior written notice of Landlord's act
or failure to act to Landlord's mortgagees of which Landlord has provided
written notice to Tenant, if any, specifying the act or failure to act on the
part of Landlord which could or would give basis to Tenant's rights, and (ii)
such mortgagees, after receipt of such notice, have failed or refused to correct
or cure the condition complained of within a reasonable time thereafter, but
nothing contained in this Section 8.5 shall be deemed to impose any obligation
on any such mortgagee to correct or cure any such condition. "Reasonable time"
as used above means and includes a reasonable time to obtain possession of the
mortgaged premises, if the mortgagee elects to do so, and a reasonable time to
correct or cure the condition if such condition is determined to exist, however,
in no event shall such time extend beyond one hundred twenty (120) days from the
date Tenant provides notice to Landlord's mortgagee(s) as aforesaid.


                                       47
<PAGE>   52


8.6      CONTINUING OFFER

         The covenants and agreements contained in this Lease with respect to
the rights, powers and benefits of a mortgagee (particularly, without limitation
thereby, the covenants and agreements contained in this Article VIII) constitute
a continuing offer to any person, corporation or other entity, which by
accepting or requiring an assignment of this Lease or by entry or foreclosure
assumes the obligations herein set forth with respect to such mortgagee, and
such mortgagee shall be entitled to enforce such provisions in its own name.
Tenant agrees on request of Landlord to execute and deliver from time to time
any agreement which may reasonably be deemed necessary to implement the
provisions of this Article VIII.

8.7      SUBMITTAL OF FINANCIAL STATEMENT

         At any time, but not more than annually during the Term of this Lease,
within fifteen (15) days after request therefor by Landlord (i.e. if requested
by Landlord's mortgagee(s)), Tenant shall supply to Landlord and/or any
mortgagee of Landlord a current financial statement, which such financial
statement may be given by Tenant to Landlord in the form of Tenant's current
annual report, or such other financial information as may be reasonably required
by any such party.

                                   ARTICLE IX
                                     DEFAULT

9.1      EVENTS OF DEFAULT BY TENANT

         It shall be an "Event of Default" under this Lease, if (i) Tenant fails
to pay Fixed Rent or additional rent for more than ten (10) days, after notice
thereof specifying such failure and that such failure may be an Event of Default
hereunder; (ii) Tenant fails to perform its other non-monetary obligations
hereunder for more than thirty (30) days after notice thereof from Landlord,
together with such additional time, if any, as is reasonably required to cure
the default if the default is of such a nature that it cannot reasonably be
cured in thirty (30) days; or (iii) if Tenant makes any assignment for the
benefit of creditors, or files a petition under any bankruptcy or insolvency
law; or (iv) if such a petition is filed against Tenant and is not dismissed
within thirty (30) days; or (v) if a receiver becomes entitled to Tenant's
leasehold hereunder and it is not returned to Tenant within ninety (90) days; or
(vi) such leasehold is taken on execution or other process of law in any action
against Tenant; then, and in any such cases, Landlord and the agents and
servants of Landlord may, in addition to and not in derogation of any remedies
for any preceding breach of covenant, immediately or at any time thereafter
while such default continues and without further notice, enter into and upon the
Premises or any part thereof in the name of the whole or mail a notice of
termination addressed to Tenant at the Premises and repossess the same as of
Landlord's former estate and expel Tenant and those claiming through or under
Tenant and remove its and their effects without being deemed guilty of any
manner of trespass and without prejudice to any remedies which might otherwise
be used for arrears of rent or prior breach of covenant, and upon such entry or
mailing as aforesaid, this Lease shall terminate, but Tenant shall remain liable
as hereinafter provided. After the occurrence of an Event of Default as
aforesaid, Tenant hereby waives all statutory rights of redemption, if any to
the extent such


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<PAGE>   53


rights may be lawfully waived, and Landlord, without notice to Tenant, may store
Tenant's effects and those of any person claiming through or under Tenant at the
expense and risk of Tenant and, if Landlord so elects, may sell such effects at
public auction or private sale and apply the net proceeds to the payment of all
sums due to Landlord from Tenant, if any, and pay over the balance, if any, to
Tenant.

9.2      TENANT'S OBLIGATIONS AFTER TERMINATION

         In the event that this Lease is terminated under any of the provisions
contained in Section 9.1, Tenant covenants to pay forthwith to Landlord, as
compensation, a single lump-sum payment equal to the excess of the net present
value of the total rent reserved for the residue of the Term (exclusive of any
unexercised Extended Term(s) remaining at the time of termination) over the fair
market rental value of the Premises (including additional rent) for said residue
of the Term estimated as of the date of termination. If Landlord does not elect
to receive a single lump-sum payment from Tenant as aforesaid, Tenant covenants
and agrees to pay punctually to Landlord all the sums and perform all the
obligations which Tenant covenants in this Lease to pay and to perform in the
same manner and to the same extent and at the same time as if this Lease had not
been terminated. In calculating the amounts to be paid by Tenant under the
foregoing covenants, Tenant shall be credited with any amount paid to Landlord
as compensation as provided in the first sentence of this Section 9.2 and also
with the net proceeds of any rents obtained by Landlord by reletting the
Premises, after deducting all Landlord's expenses in connection with such
reletting, including, without implied limitation, all repossession costs,
brokerage commissions, fees for legal services and expense of preparing the
Premises for such reletting, it being agreed by Tenant that Landlord may (i)
relet the Premises or any part or parts thereof for a term or terms which may,
at Landlord's option, be equal to or less than or exceed the period which would
otherwise have constituted the balance of the Term and may grant such
concessions and free rent as Landlord in its sole judgment considers advisable
or necessary to relet the same, and (ii) make such alterations, repairs and
decorations in the Premises as Landlord in its sole judgment considers advisable
or necessary to relet the same, and no action of Landlord in accordance with the
foregoing on failure to relet or to collect rent under reletting shall operate
or be construed to release or reduce Tenant's liability as aforesaid. If
required by Massachusetts law, and to the extent required by Massachusetts law,
Landlord will use reasonable efforts to mitigate its damages hereunder, except
as hereinafter provided in the next following paragraph.

         So long as at least twelve (12) months of the Term remain unexpired at
the time of such termination, in lieu of any other damages of indemnity and in
lieu of full recovery by Landlord of all sums payable under all the foregoing
provisions of this Section 9.2, Landlord may, by written notice to Tenant, at
any time after this Lease is terminated under any of the provisions contained in
Section 9.1, or is otherwise terminated for breach of any obligation of Tenant
and before such full recovery, elect to recover, and Tenant shall thereupon pay,
as liquidated damages, an amount equal to the aggregate of the Fixed Rent and
additional rent accrued under Article IV in the twelve (12) months ended next
prior to such termination plus the amount of Fixed Rent and additional rent of
any kind accrued and unpaid at the time of termination and less the amount of
any recovery by Landlord under the foregoing provisions of this Section 9.2 up
to the time of payment of such liquidated damages, Tenant agreeing that Landlord
shall have no obligation to

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<PAGE>   54

use reasonable efforts to mitigate its damages in the event Landlord so elects
to proceed under the provisions of this paragraph.

         Nothing contained in this Lease shall, however, limit or prejudice the
right of Landlord to prove and obtain in proceedings for bankruptcy or
insolvency by reason of the termination of this Lease, an amount equal to the
maximum allowed by any statute or rule of law in effect at the time when, and
governing the proceedings in which, the damages are to be proved, whether or not
the amount be greater, equal to, or less than the amount of the loss or damages
referred to above.

                                    ARTICLE X
                                  MISCELLANEOUS

10.1     TITLES

         The titles of the Articles are for convenience and are not to be
considered in construing this Lease.

10.2     NOTICE OF LEASE

         Concurrently with the executing of this Lease, Landlord and Tenant have
executed and recorded (or shall execute and record) a notice of lease in the
form attached hereto as Exhibit T. If this Lease is terminated before the Term
expires the parties will execute an instrument in such form acknowledging the
date of termination.

10.3     NOTICES FROM ONE PARTY TO THE OTHER

         No notice, approval, consent requested or election required or
permitted to be given or made pursuant to this Lease shall be effective unless
the same is in writing. Communications shall be addressed, if to Landlord, at
Landlord's Address with a copy to David Barry Connolly, Esq., Hinckley, Allen &
Snyder LLP, 28 State Street, Boston, Massachusetts 02109, or at such other
address as may have been specified by prior notice to Tenant and, if to Tenant,
at Tenant's Address with a copy to Robert Tuchmann, Esq., Hale and Dorr LLP, 60
State Street, Boston, MA 02109, or at such other place as may have been
specified by prior notice to Landlord. Any communication so addressed shall be
deemed duly served if actually received or delivery is refused at the foregoing
addresses mailed by registered or certified mail, return receipt requested,
delivered by hand, or by overnight express service by a courier providing a
receipt of delivery.

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<PAGE>   55


10.4     BIND AND INURE

         The obligations of this Lease shall run with the land, and this Lease
shall be binding upon and inure to the benefit of the parties hereto and their
respective heirs, successors and assigns, except that the Landlord named herein
and each successive owner of the Premises shall be liable only for the
obligations accruing during the period of its ownership, said liability
terminating as to future liability upon termination of such ownership and
passing to the successor in ownership. Neither the Landlord named herein nor any
successive owner of the Premises whether an individual, trust, a corporation or
otherwise shall have any personal liability beyond their equity interest in the
Premises.

10.5     NO SURRENDER

         The delivery of keys to any employees of Landlord or to Landlord's
agent or any employee thereof shall not operate as a termination of this Lease
or a surrender of the Premises.

10.6     NO WAIVER, ETC.

         The failure of Landlord or of Tenant to seek redress for violation of,
or to insist upon the strict performance of any covenant or condition of this
Lease or, with respect to such failure of Landlord, any of the Rules and
Regulations or Park Covenants referred to in Section 6.1.4, whether heretofore
or hereafter adopted by Landlord, shall not be deemed a waiver of such violation
nor prevent a subsequent act, which would have originally constituted a
violation, from having all the force and effect of an original violation, nor
shall the failure of Landlord to enforce any of said Rules and Regulations or
Park Covenants against any other tenant in the Park be deemed a waiver of any
such Rules or Regulations or Park Covenants, as applicable. The receipt by
Landlord of Fixed Rent or additional rent with knowledge of the breach of any
covenant of this Lease shall not be deemed a waiver of such breach by Landlord,
unless such waiver be in writing signed by Landlord. No consent or waiver,
express or implied, by Landlord or Tenant to or of any breach of any agreement
or duty shall be construed as a waiver or consent to or of any other breach of
the same agreement or duty in a previous or subsequent instance, or any other
agreement or duty.

10.7     NO ACCORD AND SATISFACTION

         No acceptance by Landlord of a lesser sum than the Fixed Rent and
additional rent then due shall be deemed to be other than on account of the
earliest installment of such rent due, nor shall any endorsement or statement on
any check or any letter accompanying any check or payment as rent be deemed as
accord and satisfaction, and Landlord may accept such check or payment without
prejudice to Landlord's right to recover the balance of such installment or
pursue any other remedy in this Lease provided.


                                       51
<PAGE>   56

10.8     CUMULATIVE REMEDIES

         The specific remedies to which Landlord may resort under the terms of
this Lease are cumulative and are not intended to be exclusive of any other
remedies or means of redress to which it may be lawfully entitled in case of any
breach or threatened breach by Tenant of any provisions of this Lease. In
addition to the other remedies provided in this Lease, Landlord shall be
entitled to the restraint by injunction of the violation or attempted or
threatened violation of any of the covenants, conditions or provisions of this
Lease or to a decree compelling specific performance of any such covenants,
conditions or provisions.

10.9     PARTIAL INVALIDITY

         If any term of this Lease, or the application thereof to any person or
circumstances shall to any extent be invalid or unenforceable, the remainder of
this Lease, or the application of such term to persons or circumstances other
than those as to which it is invalid or unenforceable, shall not be affected
thereby, and each term of this Lease shall be valid and enforceable to the
fullest extent permitted by law.

10.10(a) LANDLORD'S RIGHT TO CURE

         If Tenant shall at any time fail to perform its obligation in
accordance with the provisions of this Lease and Tenant does not commence the
cure of such failure within thirty (30) days of notice thereof (except in the
event of emergencies), and thereafter diligently prosecute such cure to
completion, then Landlord shall have the right, but shall not be obligated, to
enter upon the Premises and to perform such obligation, notwithstanding the fact
that no specific provision for such substituted performance by Landlord is made
in this Lease with respect to such default. In performing such obligation,
Landlord may make any payment of money or perform any other act. All sums so
paid by Landlord (together with interest at the rate set forth in Section 4.3
hereof), and all necessary incidental reasonable third party costs and expenses
in connection with the performance of any such acts by Landlord, shall be deemed
to be additional rent under this Lease and shall be payable to Landlord
immediately on demand. Landlord may exercise the foregoing rights without
waiving any other of its rights or releasing Tenant from any of its obligations
under this Lease.

10.10(b) TENANT'S RIGHT TO CURE

         If Landlord shall at any time fail to perform any of Landlord's
obligations in accordance with the provisions of this Lease relating to the
Premises and Tenant has provided Landlord and any mortgagee on the Property of
which Tenant has been give notice, with thirty (30) days written notice to cure
such default and Landlord or Landlord's mortgagee does not commence the cure of
such failure as soon as reasonably practicable and thereafter diligently
prosecute such cure to completion, then Tenant shall have the right, but not the
obligation, to cure any such default for the account of Landlord. If Tenant
shall undertake such performance, Landlord shall reimburse Tenant for all costs
and expenses reasonably incurred by Tenant in connection with

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<PAGE>   57

such performance within thirty (30) days after receipt of an invoice therefor
from Tenant (together with any such back up documentation reasonably requested
by Landlord). If Landlord fails to reimburse Tenant within said thirty (30) day
period, then Tenant shall be entitled to offset the unreimbursed costs against
fifteen percent (15%) of the monthly Fixed Rent due hereunder until such costs
due to Tenant hereunder have been reimbursed in full.

10.11    ESTOPPEL CERTIFICATE

         Tenant agrees on the Commencement Date, and from time to time
thereafter, upon not less than thirty (30) days' prior written request by
Landlord, to execute, acknowledge and deliver to Landlord a statement in writing
in substantially the form attached hereto as Exhibit G, certifying if true (and
where not true, indicating where not true), as follows: that this Lease is
unmodified and in full force and effect; that except as set forth in this Lease,
Tenant has no defenses, offsets or counterclaims against its obligations to pay
the Fixed Rent and additional rent and to perform its other covenants under this
Lease; that there are no uncured defaults of Landlord or Tenant under this Lease
(or, if there are any defenses, offsets, counterclaims, or defaults, setting
them forth in reasonable detail); and the dates to which the Fixed Rent,
additional rent and other charges have been paid. Any such statements delivered
pursuant to this Section 10.11 may be relied upon by any prospective purchaser
or mortgage of premises which include the Premises or any prospective assignee
of any such mortgagee.

10.12    WAIVER OF SUBROGATION

         Landlord and Tenant mutually agree, with respect to any hazard which is
covered by casualty or property insurance then being carried by them, or
required to be carried hereunder (whether or not such insurance is then in
effect) to release each other from any and all claims with respect to such loss;
and they further mutually agree that their respective insurance companies shall
have no right of subrogation against the other on account thereof. If extra
premium is payable by either party as a result of this provision, the other
party shall reimburse the party paying such premium the amount of such extra
premium. The parties further agree that if said waiver of subrogation shall be
unobtainable or unenforceable or shall void the respective policies, then their
respective insurance policies shall not be invalidated, and said waiver shall
become null and void and of no further force and effect.

10.13    BROKERAGE

         Tenant represents and warrants to Landlord, and Landlord represents and
warrants to Tenant, that it has dealt with no broker, other than such broker(s)
listed in Section 1.1, in connection with this transaction and agrees to defend,
indemnify and save the other party harmless from and against any and all claims
for a commission arising out of this Lease made by anyone, other than such
broker(s) in Section 1.1. Landlord shall be responsible for payment of all fees
and commissions payable to such broker(s) in accordance with the terms of those
certain Agreements dated November 14, 2000 and October 31, 1997 and executed by
and between Landlord, Meredith & Grew and Grubb & Ellis.


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<PAGE>   58

10.14    ACCESS AND SECURITY SYSTEM

         Subject to the terms and provisions of this Lease, Tenant shall have
twenty-four (24) hours, seven (7) days per week, access to the Premises. If
desired, Tenant shall be responsible for providing its own security system and
card access system within the Premises as part of the Tenant's Work.

10.15    ENTIRE AGREEMENT

         This instrument contains the entire and only agreement between the
parties as to the Premises, and no oral statements or representations or prior
written matter not contained in this instrument shall have any force or effect.
This Lease shall not be modified in any way except by a writing subscribed by
both parties.

10.16    GOVERNING LAW

         This Lease shall be governed by and construed and enforced in
accordance with the laws and courts of the Commonwealth of Massachusetts.

10.17    ADDITIONAL REPRESENTATIONS

         Landlord represents and warrants to Tenant as follows:

         (a) that Landlord has the right and authority to enter into this Lease
and grant Tenant possession of the Premises and other rights set forth herein;

         (b) that Landlord is the fee simple owner of the Lot and that Landlord
(or its affiliate(s) or an affiliate(s) of The Gutierrez Company) are the fee
simple owners of the Park;

         (c) that the Premises, the Building (including all common areas,
entrances, restrooms, elevators, water fountains and signage), the Building
Parking Area and the Lot will, upon Substantial Completion and issuance of all
necessary permits and approvals required to be obtained from any and all
necessary governmental agencies prior to occupancy of the Premises by Tenant,
including without limitation, a certificate of occupancy from the Town of
Bedford, Massachusetts which allows Tenant to use and occupy the Premises as
specified in Article III hereof, comply with all dimensional, use, parking,
loading and other zoning requirements of the Town of Bedford, Massachusetts, and
all applicable building codes and governmental requirements, including without
limitation the regulations of the Americans with Disabilities Act of 1990 (ADA);
and

         (d) that, upon Substantial Completion, the Building's structural
components and Building systems shall be in good working order.


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<PAGE>   59

10.18    PARKING

         Tenant's occupancy of the Premises shall initially include the use of
508 parking spaces to be expanded to 653 parking spaces when permitted by
lifting of the MEPA Limitation (as hereinafter defined) allowing for the
construction and use of additional parking, which Landlord shall diligently
pursue. Tenant's parking spaces, specifically including sufficient paved area to
accommodate up to 653 spaces, (which shall include visitor spaces in front of
the Building) shall be known and referred to in this Lease as the "Building
Parking Area," and shall be shown as such on the Landlord's Plans. As set forth
in Section 2.1 hereof, the Building Parking Area shall be used by Tenant in
common with other tenants of the Park. Upon Tenant giving Landlord at least
sixty (60) days prior written notice, Landlord agrees to provide traffic control
personnel at peak hours to enforce Tenant's rights to exclusively park in the
Building Parking Area, the costs thereof shall be reimbursable to Landlord
pursuant to Sections 4.2 and 5.1.2 hereof.

10.19    RIGHT OF FIRST OFFER

         Landlord hereby grants to Tenant but specifically not to any subtenant
or any assignee (that is not a Permitted Transferee) the following right with
regard to the Premises or any portion thereof so long as in any case (i) there
does not then exist an Event of Default under this Lease, (ii) this Lease is in
full force and effect, and (iii) Tenant is then leasing at least seventy-five
percent (75%) of the Premises. In the event Landlord shall decide to offer for
sale the Premises, or any portion thereof, Landlord shall forthwith give notice
to Tenant of its intention to sell the same at Landlord's specified price
("Landlord's Price"). Tenant shall have the right, for a period of fifteen (15)
calendar days, or in the last year of the Term or of any Extended Term for a
period of ten (10) calendar days, after such notice of intention to sell, to
notify Landlord of Tenant's interest in purchasing the same at Landlord's Price.
If (i) Tenant so notifies Landlord in writing, and (ii) Landlord and Tenant
agree on terms and conditions of purchase and sale within fifteen (15) calendar
days of such Tenant notification, or in the last year of the Term or of any
Extended Term within ten (10) calendar days of such Tenant notification, Tenant
shall post with Landlord a ten percent (10%) deposit and the Premises, or such
portion thereof, shall be sold by Landlord to Tenant, in the same condition as
at the time of the posting of the deposit, within sixty (60) days of Tenant's
acceptance at that price and upon those terms and conditions. If Tenant does not
accept Landlord's Price, Tenant may within a period of fifteen (15) calendar
days, or in the last year of the Term or of any Extended Term ten (10) calendar
days, after such notice of Landlord's intention to sell, specify a price to
Landlord (the "Tenant's Price"). If (i) Tenant so notifies Landlord, and (ii)
Landlord and Tenant agree on the Tenant's Price and terms and conditions of
purchase and sale within fifteen (15) calendar days of said Tenant notification,
or in the last year of the Term or of any Extended Term within ten (10) calendar
days of said Tenant notification, Tenant shall post with Landlord a ten percent
(10%) deposit and the Premises, or such portion thereof, shall be sold by
Landlord to Tenant, in the same condition as at the time of the posting of the
deposit, within sixty (60) calendar days of such Tenant's offer at the Tenant's
Price. Provided, however, that if Tenant thereafter defaults in its obligations
to Landlord under this subsection, Landlord shall retain as liquidated damages
the Tenant's deposit and all interest earned thereon, and Tenant shall pay to
Landlord as additional rent hereunder the costs and

                                       55
<PAGE>   60

expenses reasonably incurred by Landlord in connection with the proposed sale to
Tenant under this subsection, and all of Tenant's rights under this Section
10.19 and the rights and options referenced in the sideletters referred to in
Section 10.20 herein and in Exhibits Q and R attached hereto shall thereafter be
null and void and of no further force and effect. If Tenant does not exercise
its option of first offer, or if Landlord and Tenant do not agree on a purchase
price and/or terms and conditions of purchase and sale, then Landlord shall
promptly after the end of such fifteen (15) calendar day period, or in the last
year of the Term or of any Extended Term within such ten (10) calendar day
period, for negotiation of terms and conditions of either the Landlord's Price
or Tenant's Price, as the case may be, notify Tenant of Landlord's Adjusted
Price, which may be the same as Landlord's Price (but not less than the lowest
price for the Premises at which Landlord has offered to sell the Premises to
Tenant within the applicable negotiation period), and Landlord shall be free for
a period of two hundred ten (210) days thereafter to enter into a purchase and
sale agreement for the sale of the Premises, or such portion thereof, and/or to
sell the Premises, or such portion thereof, subject to this Lease, to any third
party for a price equal to or greater than the Landlord's Adjusted Price with
closing to take place within a reasonable period of time thereafter. After such
two hundred ten (210) day period, unless the Lease is sooner terminated, thus
extinguishing this Right of First Offer, such Right of First Offer will be
reinstated. (Upon reinstatement of such Right of First Offer, if Landlord still
wishes to sell the Premises or any portion thereof, it shall re-offer for sale
the Premises, or any portion thereof, to Tenant at any Landlord's Price which
Landlord may in its sole discretion then determine, and Tenant's rights may be
exercised as previously set forth in this Section 10.19, except that Tenant's
period of notification to Landlord of its interest in purchasing (i) at
Landlord's Price, or (ii) to specify an alternate Tenant's Price shall be five
(5) calendar days). Landlord and Tenant shall use good faith efforts to
negotiate the terms of the purchase and sale agreement and the purchase price.

         If Tenant exercises its option of first offer pursuant to this Section
10.19, the purchase price shall be paid by certified check or checks drawn by a
Boston bank or banks on the Federal Reserve Bank of Boston or in such other
manner as will make the consideration available in Boston to Landlord for
investment on the Closing Date, and the Premises in the same condition as at the
time the Deposit was made shall be simultaneously conveyed on the Closing Date
by a good and sufficient quitclaim deed running to Tenant delivered at the
offices of Hinckley, Allen, & Snyder LLP, 28 State Street, Boston, Massachusetts
02109, or such other location in the metropolitan Boston area selected by
Tenant, conveying a good and clear record and marketable title thereto subject
only to, and with the benefit of, the following matters affecting the Premises
on the closing date (the "Permitted Encumbrances"):

         l. Rights, easements, covenants, agreements and restrictions
specifically including but not limited to parking rights and easements,
covenants and restrictions necessary or convenient for the development,
construction and use of additional office buildings within the Park and rights,
easements, covenants, agreements and restrictions affecting the Premises on the
Term Commencement Date, but the same shall not include any leasehold interests
therein except for this Lease and any other leases for occupancy of space within
the Building.

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<PAGE>   61

         2. Rights, easements, restrictions, covenants and agreements hereafter
affecting the Premises so far as in force and applicable on the closing date,
which do not secure or create a voluntary lien for the payment of money.

         3. Real estate taxes and municipal betterments not yet due and payable
assessed or to be assessed upon the Premises.

         4. Balances, if any, remaining due and unpaid on account of betterment
assessments on the Premises.

         5. Laws and regulations of any government authority.

         6. Any changes in the Premises which may have occurred as a result of,
and any easements or restrictions imposed by, takings by eminent domain.

         Closing adjustments of the usual and customary items shall be made
between the parties taking into account the provisions of this Lease if
applicable and the respective obligations of the parties with respect to the
payment of such items.

         If the Landlord shall be unable to give title or to make conveyance, or
to deliver possession, all as herein stipulated, or if at the time for delivery
of the deed the Premises does not conform with the provisions hereof, the
Landlord shall use commercially reasonable efforts to remove any defects in
title, or to deliver possession as provided herein, or to make the said Premises
conform to the provisions hereof, as the case may be, and thereupon the time for
performance hereof shall be extended for a period of 60 days. To enable the
Landlord to make conveyance as herein provided, the Landlord shall, at the time
of delivery of the deed, use up to a maximum of one hundred thousand dollars
($100,000.00) of the purchase money or any portion thereof to clear the title of
any or all encumbrances or interests, provided that all instruments so procured
are recorded simultaneously with the delivery of said deed or arrangements are
made reasonably satisfactory to Tenant and its counsel to procure the same
within a reasonable period of time after the closing.

         In regard to mortgages to which the Premises is subject immediately
prior to the purchase, there shall be paid directly by official bank or
certified check to the holder of such mortgage, for the purpose of discharging
the same, such portion of the purchase price as is necessary to pay all amounts
(including without limitation any prepayment penalties) secured by such mortgage
relating to the Premises, and the remaining balance of the purchase price shall
be paid to Landlord. Tenant shall have the right, at Tenant's option, and with
the consent of any applicable mortgagee, to assume any mortgages thereon, in
which event the purchase price shall be reduced by the outstanding balance of
principal, interest and other charges under such mortgages as of the closing
date provided, however, that Tenant may assume said mortgage only if the
mortgagee simultaneously releases Landlord, its Affiliates or any other parties
liable therefor from any further obligation on the mortgage debt.


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<PAGE>   62

         Tenant agrees, at Landlord's request, to allow Landlord to attempt to
effectuate a tax free exchange at Landlord's sole risk in connection with the
exercise by Tenant of its first offer right contained in this Lease, provided,
however, that Landlord pays all of Tenant's reasonable costs in connection with
such tax free exchange. Tenant shall cooperate with Landlord in connection
therewith provided that the same does not result in substantial delays in
completing the purchase and Tenant in its sole reasonable opinion bears no
additional liability as a result thereof.

         10.19.1 AFFILIATES. The foregoing rights of Tenant set forth in Section
10.19 shall not be applicable to (i) transfers and sales to Affiliates of
Landlord or Affiliates of The Gutierrez Company, (ii) transfers or sales to any
party of any limited partnership interest in the limited partnership which
transferee is Landlord or the affiliates of the General Partner, family members
or affiliates of the General Partner or of any limited partner, or employees of
the General Partner(s) or limited partners, (iii) transfers, or sales of any
general partnership interest in the limited partnership which is Landlord to an
Affiliate, (iv) the placing of any bona fide mortgage on the Premises or any
portion thereof or to the foreclosure thereof or to the delivery of a deed or
any other transfer in lieu of such foreclosure, or (v) any sale and leaseback
transaction, (vi) any exercise of an option to acquire an ownership interest in
the Premises pursuant to any equity or convertible mortgage, and (vii) to any
partial sale of an undivided interest or any joint venture transaction in lieu
of conventional refinancing of the Building.

         This Right of First Offer shall be extinguished by any foreclosure or
deed in lieu of foreclosure given to any mortgagee of the Premises or any part
thereof. The Right of First Offer shall not be binding on any mortgagee of the
Premises or any part thereof or any party obtaining title to the Premises or any
part thereof from such mortgagee, provided however, that Landlord shall give
notice to Tenant (i) ten (10) days before the grant by Landlord of any deed in
lieu of such foreclosure, and (ii) forthwith (which notice may be given by
mortgagee as well as Landlord) of the institution of any foreclosure under any
mortgage of the Premises. Any other such transfer or sale shall be subject to
this Right of First Offer.

         As used herein an Affiliate shall mean as to any Landlord (i) Arturo J.
Gutierrez, John A. Cataldo, or members of their immediate family (as defined
below); (ii) the legal representative, successor or assignee of, or any trustee
of a trust for the benefit of Arturo J. Gutierrez, John A. Cataldo, or members
of their immediate family; or (iii) any entity of which a majority of the voting
interests is owned by any one or more of the persons referred to in the
preceding clauses (i) and (ii). Immediate family shall mean, with respect to any
person, his spouse, children, adopted children, parents, parents-in-law,
grandchildren and great-grandchildren.

10.20    LETTER AGREEMENTS

         The Landlord is delivering to Tenant simultaneously with this Lease,
two (2) Letter Agreements in the form attached hereto as Exhibit "O"
(hereinafter Letter Agreements), and Landlord shall use commercially reasonable
efforts to enforce such Letter Agreements to the extent necessary for the
protection of the Tenant's rights thereunder. In no event however, shall any
default or failure to fulfill any of the agreements set forth in such Letter
Agreements by Landlord or others give rise to a default by Landlord under this
Lease.

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<PAGE>   63

         IN WITNESS WHEREOF, the parties hereto have duly executed this Lease as
of this ___ day of November, 2000.

                                      LANDLORD:
                                      BEDFORD WOODS LIMITED
                                      PARTNERSHIP I
                                      BY: THE GUTIERREZ COMPANY,
                                          GENERAL PARTNER


                                      By: /s/ Arturo J. Gutierrez
                                         --------------------------------
                                      Its:  President
                                      Dated:  November 17, 2000

                                      TENANT:
                                      RSA SECURITY, INC.


                                      By: /s/ John F. Kennedy
                                         --------------------------------

                                      Its:  Chief Financial Officer

                                      Dated:  November 17, 2000



                                       59

<PAGE>   64


                                   EXHIBIT "A"

               PLANS SHOWING TENANT'S SPACE, THE LOT AND THE PARK

         Plans entitled "C1.1, C2.1, C2.2, C3.1, C3.2, C4.1, C4.2, C5.1, C5.2,
C6.1, C6.2, C6.3, C6.4 Revised Notice of Intent, The Gutierrez Company, Building
3, Bedford Woods, Bedford, MA dated September 29, 1999 revised November 16, 1999
and revised November 8, 2000 and November 10, 2000" by Symmes, Maini & McKee
Associates; Park Plan entitled Bedford Woods, Middlesex Turnpike, Bedford, MA,
Lot Plan by Symmes, Maini & McKee Associates dated November 10, 2000; Proposed
subdivision plan entitled "Plan of Land in Bedford, MA, Prepared for The
Gutierrez Company dated November 13, 2000" by Hancock Survey Associates, Inc.




<PAGE>   65


                                  EXHIBIT "A-1"

                          LEGAL DESCRIPTION OF THE LOT



         A certain parcel of land located on Middlesex Turnpike in the Bedford
Woods Office Park, Bedford, Massachusetts shown as Lot 1-3 on that certain plan
entitled "Plan of Land in Bedford, MA prepared for The Gutierrez Company"
prepared by Hancock Survey Associates, Inc. Scale 1" = 100' dated November 13,
2000 and to be recorded with the Middlesex South Registry of Deeds when executed
by the Town of Bedford, Massachusetts Planning Board. Said Lot 1-3 contains
approximately 31.1611 acres according to said plan (a copy of which is attached
hereto and made a part hereof). Landlord and Tenant hereby acknowledge and agree
that this Exhibit A-1 shall be replaced by amendment to this Lease upon creation
of the Lot and recording of said plan.

<PAGE>   66


                                  EXHIBIT "B-1"

                               BASE BUILDING PLANS

         Attached hereto are plans entitled "Building 3, Bedford Woods, Bedford,
MA, Tenant Review A1.1, A1.2, A1.3, A1.4, A2.1, A3.1" dated November 13, 2000
prepared by Symmes, Maini & McKee Associates.





<PAGE>   67



                                  EXHIBIT "B-2"



                        GUTIERREZ CONSTRUCTION CO., INC.

                             OUTLINE SPECIFICATIONS
                                       FOR
                                  BEDFORD WOODS
                                   BUILDING #3
                             BEDFORD, MASSACHUSETTS
                                NOVEMBER 14, 2000



                                       63

<PAGE>   68

                             OUTLINE SPECIFICATIONS

                                    I N D E X


                                                                        PAGE NO.
                                                                        --------
DIVISION 1 - GENERAL REQUIREMENTS
             Section 1A - Scope of the Work
             Section 1B - Assumptions
             Section 1C - Area Summary

DIVISION 2 - SITE WORK
             Section 2A - Site Preparation and Earthwork
             Section 2B - Site Improvements
             Section 2C - Lawns and Plantings
             Section 2D - Site Drainage
             Section 2E - Site Utilities
             Section 2F - Irrigation

DIVISION 3 - CONCRETE
             Section 3A - Concrete
             Section 3B - Precast Concrete

DIVISION 5 - METALS
             Section 5A - Structural Steel
             Section 5B - Miscellaneous and Ornamental Iron

DIVISION 6 - CARPENTRY
             Section 6A - Rough Carpentry
             Section 6B - Millwork

DIVISION 7 - MOISTURE PROTECTION
             Section 7A - Roofing and Flashing
             Section 7B - Waterproofing, Dampproofing and Caulking

DIVISION 8 - DOORS, WINDOWS AND GLASS
             Section 8A - Wood Doors
             Section 8B - Metal Door Frames
             Section 8C - Finish Hardware
             Section 8D - Aluminum Entrance
             Section 8E - Glass and Glazing
             Section 8F - Overhead Doors


                                       64

<PAGE>   69


Outline Specifications - Index

DIVISION 9 - FINISHES
             Section 9A - Resilient Base
             Section 9B - Acoustical
             Section 9C - Painting and Vinyl Wallcovering
             Section 9D - Gypsum Drywall
             Section 9E - Exterior Soffits
             Section 9F - Insulation
             Section 9G - Carpeting
             Section 9H - Ceramic Tile

DIVISION 10 - SPECIALTIES
             Section 10A - Toilet Partitions
             Section 10B - Toilet Accessories
             Section 10C - Dock Equipment

DIVISION 12 - FURNISHINGS
             Section 12A - Blinds

DIVISION 14 - CONVEYING SYSTEM
             Section 14A - Elevator

DIVISION 15 - MECHANICAL
             Section 15A - Plumbing
             Section 15B - Heating, Ventilating and Air Conditioning
             Section 15C - Sprinklers

DIVISION 16 - ELECTRICAL
             Section 16A - Electrical Work

DIVISION 17 - EXCLUSIONS


                                       65

<PAGE>   70

                                   DIVISION 1

                              GENERAL REQUIREMENTS

SECTION 1A - SCOPE OF THE WORK

1A-01    Gutierrez Construction Co., Inc. will provide all labor, material and
         equipment necessary to complete the construction of the subject
         building in accordance with these Outline Specifications dated May 19,
         2000, the preliminary drawings as prepared by Symmes, Maini & McKee
         Associates, Inc. dated November 13, 2000, and the Site Plan of Land
         dated February 4, 1999, revised November 16, 1999 and November 8, 2000
         as prepared by Symmes, Maini & McKee Associates, Inc.


SECTION 1B - ASSUMPTIONS

1B-01    All required utilities of adequate size and capacity will be available
         at the property line or in the Subdivision Road immediately adjacent to
         the property line.

1B-02    This proposal is based on Class II-C construction as specified in the
         Massachusetts State Building Code.


SECTION 1C - AREA SUMMARY

1C-01    The building is a four (4) story, "open shell" office building for a
         total of 188,236 square feet.

1C-02    Parking spaces to be provided at 3.18 spaces per 1,000 square feet of
         building area.

1C-03    Provide two (2) truck docks and a dumpster pad.


                                       66

<PAGE>   71


                                   DIVISION 2

                                    SITE WORK

SECTION 2A - SITE PREPARATION AND EARTH WORK

2A-01    The building site, including landscaped areas, shall be graded
         to + / -0.1' elevations with positive drainage, free of pockets, using
         existing granular materials. All grading is to be done in accordance
         with the site plan developed from the preliminary drawings adjusted so
         as to produce a balanced site.

2A-02    The building pad shall be graded and compacted with six inches (6") of
         suitable granular material to an elevation of minus five inches (-5")
         from finished floor elevation. Compaction shall be 95% proctor method,
         ASTM D 1557.

2A-03    All paved areas shall receive a minimum of eight inches (8") of
         suitable granular material compacted to 92% of its maximum density.


SECTION 2B - SITE IMPROVEMENTS

2B-01    Parking areas shall be paved with two and one half inches (2 1/2") of
         bituminous concrete to consist of one and one-half inches (1 1/2")
         binder coarse and one inch (1") finish. Material and workmanship shall
         be based on State Highway Department specifications.

2B-02    Roads shall be paved as specified for parking areas.

2B-03    Sidewalks shall be paved with four inches (4") of concrete around the
         building and 2 1/2" bituminous paving at parking lots.

2B-04    All necessary curbing shall be granite or bituminous berm as shown on
         the drawings.


SECTION 2C - LAWNS AND PLANTINGS

2C-01    Lawns and planting will be designed to meet the Town Planning Board's
         requirements per Symmes, Maini & McKee Associates, Inc.'s February 4,
         1999 Site Plans.


                                       67

<PAGE>   72


SECTION 2D - SITE DRAINAGE

2D-01    Parking areas, roadways and trucking areas shall be surface drained and
         underground drainage shall be installed as shown on the Site Plans.

                       DIVISION 2 - SITE WORK (Continued)


SECTION 2E - SITE UTILITIES

2E-01    Domestic water service and fire sprinkler shall be from a water main at
         the property line. The water meter and piping shall be sized to suit
         the building requirements. Fire sprinkler service will be sized per
         NFPA 13 for light hazard.

2E-02    Sanitary sewer shall be connected to the existing sewer main at the
         property line.

2E-03    Electrical service shall be provided by the electric UTILITY COMPANY'S
         pad-mounted transformer.

2E-04    Provide six (6) 4" PVC Conduits for telephone/fiber optics service
         entrance.

2E-05    Gas service will be provided by the local utility company.

2E-06    Provide two (2) 4" PVC Conduits between Building #3 and Building #4 for
         Tenant's use.


SECTION 2F - IRRIGATION

2F-01    An automatic, underground lawn irrigation system will be provided for
         all lawn areas adjacent to the building and at the main entrance.


                                       68
<PAGE>   73

                                   DIVISION 3

                                    CONCRETE


SECTION 3A - CONCRETE

3A-01    Provide all plain and reinforced concrete work, including all necessary
         form work, sleeves, inserts, etc. Concrete material shall be 3,000
         p.s.i.

3A-02    Floor slab-on-grade shall be five inch (5") thick concrete reinforced
         with welded wire fabric for a live load rating of 200 p.s.f. Second,
         third and fourth floor slabs shall be designed for a load of 100 p.s.f.
         with live load reduction allowed by the Massachusetts State Code.

3A-03    Foundations shall be continuous reinforced concrete footings and walls
         and individual spread reinforced concrete footings under columns. All
         foundations shall bear on engineered fill, natural soil or ledge.

3A-04    Floors shall meet the following level and flatness criteria. Slab on
         grade shall be within FF (flatness) 25 and F1 (level) 20. Suspended
         slabs shall be within FF (flatness) = 20.


SECTION 3B - PRECAST CONCRETE

3B-01    Precast concrete exterior spandrel panels shall be designed to meet
         wind loading as required by the governing code(s) and shall have an
         exposed aggregate finish as approved by the Architect and Owner.


                                       69

<PAGE>   74


                                   DIVISION 5

                                     METALS

SECTION 5A - STRUCTURAL STEEL

5A-01    All structural steel work shall conform to the "Specifications for
         Design, Fabrication and Erection of Structural Steel for Buildings" of
         the American Institute of Steel Construction and the requirements of
         the local building code. All steel shall be ASTM-A-36.

5A-02    The structure shall be steel columns, beams or trusses, and bar joists.
         The building shall be designed in accordance with the building code
         requirements.

5A-03    The roof construction shall be 22 gauge, prime-painted metal roof
         decking. Roof shall be designed to support a live load of 35 p.s.f.
         plus the loading required for a rubber or EPDM ballasted roofing
         system.

5A-04    Second, third and fourth floor framing systems shall be designed to
         support a total live and dead load of 100 p.s.f. with live load
         reduction allowed by the Massachusetts State Code. Floor decking shall
         be 28 gauge Fab-Form metal deck or equal.

5A-05    Provide thirteen feet (13'-11"') from slab to slab at the first, second
         and third floors. Provide thirteen feet eleven inches (13'-11") from
         fourth floor slab to the top of the roof steel at the high point.

5A-06    Provide wind framing and attachment for precast concrete.

5A-07    Provide framing and supports for roof top equipment as may be required.


SECTION 5B - MISCELLANEOUS AND ORNAMENTAL IRON

5B-01    Provide manhole and catch basin frames and covers where required.

5B-02    Stairs shall be metal pan, concrete filled type. Stairs shall be
         provided with integral nosings. Handrails shall be tubular steel,
         except as otherwise indicated on the drawings. One stair will service
         the roof.

5B-03    All necessary channel iron supports and hanging rods for toilet
         partitions and glass entrances shall be provided.

5B-04    Provide elevator sill angles.

5B-05    Provide one ornamental stair from the first to the second floor at the
         Atrium. Alternately, the Tenant may elect to take a cash allowance.


                                       70

<PAGE>   75

                                   DIVISION 6

                                    CARPENTRY

SECTION 6A - ROUGH CARPENTRY

6A-01    Provide all wood blocking and rough carpentry required.

6A-02    Install wood doors, metal door frames and finish hardware.

6A-03    Install toilet partitions.


SECTION 6B - MILLWORK

6B-01    All men's and women's toilet rooms shall have Corian lavatory counter
         tops with integral bowls, backsplash, endsplash and apron.

6B-03    Provide a four inch (4") oak base at the walls of the lobbies and
         toilet room vestibule areas, or alternate type base as selected.
         Alternately, the Tenant may elect to take a cash allowance.

6B-04    Provide a plastic laminate sill at all perimeter wall office windows.

6B-05    Provide a plastic laminate backsplash at the mop sink in the janitor's
         closet.

                                       71

<PAGE>   76

                                   DIVISION 7

                               MOISTURE PROTECTION


SECTION 7A - ROOFING AND FLASHING

7A-01    The roof shall be insulated to yield a "U" factor of .06. Roof loading
         is to be in accordance with the building code requirements. The roofing
         shall be a ballasted rubber or EDPM roofing system as manufactured by
         Carlysle, Firestone, General Tile or approved equal. A ten (10) year
         labor and material and an additional ten (10) years on material,
         manufacturer's standard guarantee is included.

7A-02    Flashing at the precast concrete parapets and HVAC equipment shall be
         provided.

7A-03    Vent pipe flashings shall be provided as necessary.


SECTION 7B - WATERPROOFING, DAMPPROOFING AND CAULKING

7B-01    Interior caulking shall be the type appropriate for the application.

7B-02    Caulk perimeter of all exterior doors and windows with monolastic,
         meric Thiokol caulking or approved equal.

7B-03    All precast concrete joints shall be caulked with monolastomeric
         Thiokol caulking or approved equal.

7B-04    Waterproof and/or dampproof the elevator pit as required.


                                       72
<PAGE>   77


                                   DIVISION 8
                            DOORS, WINDOWS AND GLASS

SECTION 8A - WOOD DOORS

8A-01    Interior base building wood doors shall be 3'0" x 8'-0" by 1 3/4" solid
         core, plain sliced, red oak and/or 3'0" x 7'0" by 1 3/4" solid core,
         stain grade oak. Provide fire rated doors as required by code. All oak
         doors are to have matching edges.

SECTION 8B - METAL DOORS AND FRAMES

8B-01    All interior base building door frames shall be welded type or three
         piece, pressed metal, single and/or double rabbet door frames with
         proper anchors for partitions. Provide fire rated frames as required by
         code.

8B-02    Provide a 3'-0" x 7'-0" metal insulated door adjacent to the loading
         dock.

SECTION 8C - FINISH HARDWARE

8C-01    Finish hardware shall be heavy duty grade Russwin, Schlage, or approved
         equal.

8C-02    Key schedule shall be per the Owner's requirements.

8C-03    Lockset to have removable cores.

SECTION 8D - ALUMINUM ENTRANCE

8D-01    Aluminum door frame assemblies, including window trim, shall be
         anodized aluminum as indicated on the drawings.

8D-02    Aluminum entrances shall be complete with all hardware (pivot hinges,
         push/pulls, closers, etc.) except cylinder, which is to be furnished
         under Section 8C, Finish Hardware.

SECTION 8E - GLASS AND GLAZING

8E-01    Glass for entrances shall be 1/4" tinted. Entrance doors shall be 3'0"
         x 7'0" with glass transom.

8E-02    Mirrors shall be provided over each lavatory at the men's and women's
         toilet rooms. In addition, women's toilet rooms shall be provided with
         a full height mirror located on the wall opposite the lavatories.

8E-03    The exterior glass shall be 1" insulating, butt glazed, tinted as
         manufactured by LOF, PPG or approved equal. Glass area shall be kept
         under 50% of the exterior wall area. Includes Manufacturer's Standard
         ten (10) year warranty for the insulated glass units.


                                       73

<PAGE>   78


                DIVISION 8 - DOORS, WINDOWS AND GLASS (Continued)


SECTION 8E - GLASS AND GLAZING  (Continued)

8E-04    The aluminum framing for glass shall be anodized aluminum with a
         thermal break as manufactured by Alumiline, Kawneer or approved equal.
         All windows are to be the fixed type.


SECTION 8F  - OVERHEAD DOORS

8F-01    Provide two (2) electrically operated, 8' x 8', insulated overhead door
         with weather seal for the truck dock.



                                       74

<PAGE>   79

                                   DIVISION 9

                                    FINISHES


SECTION 9A - RESILIENT BASE FOR THE BASE BUILDING

9A-01    Resilient base shall be 4" high, vinyl cove or straight as applicable.


SECTION 9B - ACOUSTICAL WORK FOR THE BASE BUILDING

9B-01    All base building toilet rooms, stairways and main lobby shall have
         lay-in, reveal edge units of 3/4" x 24" x 24", mineral acoustic tile.
         Suspension system shall be exposed grid "T" suspension system. Ceiling
         height shall be 9'-0", except toilet rooms shall be 7'-6". Tile and
         suspension system shall be white.


SECTION 9C - PAINTING FOR THE BASE BUILDING

9C-01    All exposed ferrous metals shall receive a primer coat and one coat of
         enamel.

9C-02    Interior painted walls are to receive two coats of latex paint. The
         lobby will be painted with Polymix 400 Series or approved equal.

9C-03    Interior, base building doors shall receive two coats of semi-gloss
         enamel paint, or one coat of sealer and two coats of polyurethane.

9C-04    Toilet room walls that are not to receive ceramic tile shall be painted
         with Polymix 400 Series or approved equal.


SECTION 9D - GYPSUM DRYWALL FOR THE BASE BUILDING

9D-01    Interior, ceiling high partitions shall be 25 ga., 2 1/2" galvanized
         metal studs, 24" O.C. with _" gypsum wallboard on each side, taped,
         sanded and ready for paint. All full-height partitions shall be 25 ga.,
         3 5/8" galvanized metal studs, 24" O.C. with _" gypsum wallboard on
         each side, taped, sanded and ready for paint. Insulation in partitions
         shall be as indicated on the drawings. Provide fire rating as required
         by code. All required fire rated walls shall be constructed with
         approved fire rated drywall assembly systems.

9D-02    The interior of the exterior walls shall be furred with metal studs,
         insulated and covered with drywall in all finished areas. The interior
         face of all precast concrete will be insulated with a minimum of 3 1/2"
         of fiberglass insulation.


                                       75

<PAGE>   80

                        DIVISION 9 - FINISHES (Continued)


SECTION 9D - GYPSUM DRYWALL FOR THE BASE BUILDING  (Continued)

9D-03    Interior steel columns will be tubular type, or "H" columns covered
         with drywall, taped, sanded and prepared for finish or exposed tube
         type.


SECTION 9E - EXTERIOR SOFFITS

9E-01    All exposed exterior soffits shall be synthetic plaster.


SECTION 9F - INSULATION

9F-01    Fiberglass blanket type insulation shall be provided behind all
         exterior walls, except behind the spandrel panels where rigid
         insulation may be used.

9F-02    Rigid insulation shall be provided at the perimeter foundation walls.


SECTION 9G - CARPETING

9G-01    An allowance of twenty-four dollars ($24.00) per square yard has been
         included for all carpet at the base building areas.


SECTION 9H - CERAMIC TILE

9H-01    Toilet rooms and showers shall have 1" x 1" or 2" x 2", unglazed,
         ceramic floor tile and 4 1/4" x 4 1/4" glazed, ceramic tile, full
         height, at wet walls. Ceramic tile to be selected from Color Group I.


                                       76

<PAGE>   81


                                   DIVISION 10

                                   SPECIALTIES


SECTION 10A - TOILET PARTITIONS

10A-01   Partitions shall be ceiling hung with a baked enamel finish. Provide
         toilet partitions as indicated on the drawings.


SECTION 10B - TOILET ACCESSORIES

10B-01   Provide brushed stainless steel accessories as indicated on the
         drawings. Accessories shall include double roll toilet paper holders,
         recessed paper towel dispenser/disposals, liquid soap dispensers,
         sanitary napkin vendors and disposals and grab bars at handicap
         toilets. Also, provide mop hooks at janitor's closets.


SECTION 10C - DOCK EQUIPMENT

10C-01   Provide two (2) mechanical edge of dock leveler. Leveler shall be
         Kelley E-Z Ramp Series STD-66, or approved equal. Dock bumper integral
         with the dock leveler shall be provided. Provide space next to truck
         dock for the compactor. Truck dock will be standard 48" height. Also,
         provide seals and/or shelters, swivel dock lights and bollards.

SECTION 10D - LOBBY ALLOWANCE

10D-01   Provide a $25,000.00 allowance for upgrades to Main Lobby finishes.


                                       77

<PAGE>   82


                                   DIVISION 12

                                   FURNISHINGS


SECTION 12A - BLINDS

12A-01   Vertical blinds shall be LouverDrape, Model EL (Elite) or approved
         equal, both traversing and rotating types.

12A-02   Blinds shall have top track only with manufacturer's standard baked
         enamel finish.

12A-03   Vertical blind blades are to be PVC solid core, 3 1/2" wide, .03"
         thickness. Color shall be manufacturer's standard color as selected by
         the Owner and Architect.

12A-04   Blinds shall be installed at all exterior wall windows.



                                       78

<PAGE>   83


                                   DIVISION 14

                                CONVEYING SYSTEM



SECTION 14A - ELEVATOR

14A-01   Two (2) standard package, 3,500 pound capacity hydraulic passenger
         elevators shall be provided at the main entrance lobby and one (1)
         standard package 5,000 pound capacity hydraulic passenger/material
         elevator near the truck dock. Speed shall be 125 feet per minute. Cab
         finish shall be stainless steel on front panels and doors, plastic
         laminate walls, and baked enamel frame and entrance doors on hall side.
         Include protective pads and hooks, handrail at rear, telephone box and
         cable, removable ceiling, certificate frame, emergency car lighting,
         exhaust fan, handicapped code requirements and 3'6" center opening
         doors.

                                       79

<PAGE>   84
                                   DIVISION 15
                                   MECHANICAL

DIVISION 15A - PLUMBING

15A-01   CODES, ORDINANCES AND PERMITS

         1.       All material and workmanship shall be in strict accordance
                  with the following codes:

                  A.  Massachusetts State Plumbing Code
                  B.  Massachusetts State Building Code
                  C.  National Fire Codes
                  D.  Requirements of the Town of Bedford, Massachusetts
                  E.  Department of Public Health

15A-02   SANITARY WASTE AND VENT SYSTEM

         1.       Interior waste and vent piping shall convey wastes to the
                  underground sanitary waste system and shall be vented through
                  the roof as required by code.

         2.       Exterior sanitary waste shall be connected to the Town's Sewer
                  System as indicated on the site plan.

15A-03   ROOF DRAINAGE SYSTEM

         1.       Interior roof drains shall be adequately sized and installed
                  to drain all roof surfaces and shall be connected to the storm
                  drain outside the building line.

15A-04   COLD AND HOT WATER SYSTEMS

         1.       Cold and hot water systems shall be installed to service all
                  fixtures and equipment indicated on the drawings requiring
                  cold and hot water.

         2.       Cold and hot water shall be sized in accordance with the
                  latest requirements of the applicable plumbing code.

Provide isolation valves at each toilet room by floor.

15A-05   GAS PIPING

         1.       Provide gas piping from the meter to the rooftop HVAC Units.

15A-06   PIPING AND FITTINGS

         1.       Piping and fittings shall be cast iron for sanitary and storm,
                  and copper for water - all conforming to the latest ASTM
                  and/or F.S. standards.

15A-07   PIPING AND DRAINAGE ACCESSORIES


                                       80

<PAGE>   85

         1.       Roof drains, wall/ground hydrants, cleanouts, and fixture
                  carriers shall be as manufactured by J.R. Smith, Josam, Zurn
                  or approved equal. pressure-reducing valves and back flow
                  preventors shall be as manufactured by Watts or approved
                  equal.


                                       81

<PAGE>   86

                      DIVISION 15 - MECHANICAL (Continued)

SECTION 15A - PLUMBING  (Continued)

15A-08   INSULATION

         1.       All above-ground cold water piping, valves and fittings shall
                  be insulated, including the air chamber. Horizontal rain
                  leaders and all roof drains shall be insulated.

15A-09   WATER METER

         1.       Water meter and piping shall be furnished and installed in
                  accordance with the Town of Bedford, Massachusetts'
                  requirements.

15A-10   PLUMBING FIXTURES

         1.       Water closets shall be wall-hung, elongated, flush valved
                  closets with 1 1/2" top spuds and exposed valves as
                  manufactured by Kohler Company or approved equal, with white,
                  open front seats, no cover.
         2.       Urinals shall be wall-hung, white with 1 1/2" top spuds,
                  exposed valves as manufactured by Kohler Company or approved
                  equal.
         3.       Lavatories shall be Intregal Corian Type included in Section
                  6B.
         4.       Drinking fountains (one on each floor) shall be electric,
                  semi-recessed, wall-mounted type as manufactured by Halsey
                  Taylor or approved equal.
         5.       Electric hot water heater(s), sized to suit the base building
                  requirements, shall be provided.
         6.       Handicap type fixtures will be provided in the toilet rooms as
                  required by applicable codes.

15A-11   TESTING

         1.       All piping systems shall be tested in accordance with the
                  applicable codes.

SECTION 15B - HEATING, VENTILATING AND AIR CONDITIONING

15B-01   Provide rooftop, variable volume, heating, ventilating and air
         conditioning to provide comfort heating and cooling on a year-round
         basis with controlled night set back and economizing features, and
         shall meet all applicable code requirements. Capacity will be based on
         350 S.F./Ton. Equipment shall be as manufactured by Trane or approved
         equal as selected by Gutierrez Construction Co., Inc. A low voltage,
         automatic temperature control system will also be provided. Includes
         HVAC distribution for the base building areas. Does not include HVAC
         distribution at tenant areas. The rooftop HVAC Units will provide gas
         fired morning warm-up to meet the requirements of the Massachusetts
         Energy Code. The rooftop HVAC Units will be provided with three feet
         (3') high vibration/insulated curbs to minimize noise and vibration.
         Rooftop units will not be operated without filters. Filters used during
         construction will be changed prior to Tenant's occupancy. The
         ventilation for the building will be designed per the Massachusetts
         State Code.

                                       82

<PAGE>   87

                       DIVISION 15 -MECHANICAL (Continued)


SECTION 15B - HEATING, VENTILATING AND AIR CONDITIONING (Continued)
-------------------------------------------------------


15B-02   DUCT WORK

         all duct work shall be galvanized steel to meet the ASHRAE standards.
         Flexible duct run-outs shall not exceed six feet (6').

15B-03   GRILLES AND DIFFUSERS

         As required for the base building.

15B-04   TOILET ROOM EXHAUST

         A toilet room exhaust system shall be installed in accordance with the
         code requirements.

15B-05   NOISE LEVELS

         The HVAC System will be designed to meet or exceed an NCR of 35 to 40.

15B-06   HEATING, VENTILATING AND AIR CONDITIONING FOR TENANT AREAS

         A zoned heating, ventilating and air conditioning system, including
         distribution duct work, diffusers, return air grilles and thermostatic
         control for general office use is not included. Duct shafts and ducts
         will be provided from the rooftop equipment to the first, second, third
         and fourth floors. Above the ceiling will be used as a return air
         plenum. Return ductwork is not anticipated.

SECTION 15C - SPRINKLERS

15C-01   An automatic wet pipe, light hazard sprinkler system shall be provided
         for the base building. System shall be designed to meet the I.S.O. and
         NFPA #13 requirements. Heads at acoustical ceilings shall be chrome
         plated, semi-recessed, pendant type located at the center one third (_)
         of the 24" x 24" ceiling tile. Heads in open areas shall be the brass
         upright type. Testing shall be in accordance with NFPA Pamphlet No. 13.
         Furnish and install tamper and flow switches. Wiring shall be by the
         electrical subcontractor. Sprinkler distribution for the tenant areas
         is not included. Stub outs will be provided on each floor for Tenant
         distribution which will be sized for a density of one hundred twenty
         square feet (120 S.F.) to one hundred fifty square feet (150 S.F.) per
         sprinkler head. Includes standpipe and fire hose connections as
         required.

                                       83

<PAGE>   88

                                   DIVISION 16

                                   ELECTRICAL

SECTION 16A - ELECTRICAL WORK

16A-01   SERVICE ENTRANCE

         The primary electric service and pad mounted transformer will be
         provided by the local utility company at no cost to Gutierrez
         Construction Co., Inc. Provide underground PVC conduit for electric and
         telephone as required by the utility companies. The secondary side of
         the electrical service will be 4,000 Amps at 480 Volt, 3-phase, 4-wire.

16A-02   CODES AND STANDARDS

         Materials and workmanship shall conform with the latest editions of the
         following applicable codes, standards and specifications:

         1.  National Board of Fire Underwriters
         2.  Underwriter's Laboratories, Inc.
         3.  National Electrical Code
         4.  National Bureau of Standards Handbook 11-30, National Safety Code
         5.  Local and State Building Codes, and all other authorities having
             jurisdiction

16A-03   RACEWAYS AND CONDUCTORS

         Generally, wiring will consist of insulated conductors installed in
         3/4" minimum size, EMT. Flexible conduit (BX) will be used for terminal
         connection at all motors. Electrical metallic tubing will be used in
         areas above hung ceilings. Aluminum conduit may be used in concealed
         areas or in areas eight feet (8') above the floor. No aluminum conduit
         will be used in concrete or underground. BX may be used where allowed
         by applicable codes. Above the ceiling is used as a return air plenum.
         Conductors will be 600 volt copper, except where otherwise noted.
         Wire/cable #2 and larger may be aluminum. The following conductors will
         be used:

         1.  Power:     #12 Minimum 75(Degree)C THWN
         2.  Lighting:  #12 Minimum 75(Degree)C THWN
         3.  Control:   #14 Minimum 75(Degree)C THW
         4.  Fixture:   #16 Minimum 90(Degree)C MTW
         5.  Alarm:     #14 Minimum 75(Degree)C THW


                                       84


<PAGE>   89


                      DIVISION 16 - ELECTRICAL (Continued)

SECTION 16A - ELECTRICAL WORK  (Continued)

16A-04   GROUNDING SYSTEM

         Grounding will consist of copper clad steel rods connected with bare
         copper cable. The grounding system will be connected to the existing
         ground in the power plant at the pad mounted transformer. The
         interconnection conductors will be built into the main feeder cable.
         Building steel and all electrical equipment enclosures will be
         grounded.

16A-05   FEEDER CIRCUITS

         Feeders will supply 480/277 volt power from the main distributor to
         distribution panels. Main service will be adequately sized to serve the
         building's requirements as specified in these outline specifications.
         Includes transient voltage surge protection at the service entrance and
         branch circuit panel boards.

16A-06   TRANSFORMERS

         Dry-type K13 rated transformers will be provided for 120/208 volt
         panels.

16A-07   PANELBOARDS

         Panelboards will be 480/277 volt, 3-phase, 4-wire and 120/208 volt,
         3-phase, 4-wire with 200% neutrals with provisions for bolt in circuit
         breakers. Panelboards will be sized for the HVAC, 2 watts per square
         foot for the 277 volt light fixtures and 6 watts per square foot at for
         120/208 volt power. Panelboards will be located in electrical closets
         on each floor.

16A-08   WIRING DEVICES, OUTLETS AND SWITCHES

         1.  Switches will be the quiet toggle type, NEMA standard.
         2.  Convenience outlets will be duplex grounding type, 20 amp rates,
             NEMA standard.
         3.  Device plates will be ivory-colored plastic.

16A-09   INDOOR LIGHTING

         Lighting will be fluorescent parabolic and/or fluorescent down lights
         for the base building. Lighting in tenant areas is not included.
         Alternately, the Tenant may elect to take a cash allowance.

16A-10   OUTDOOR LIGHTING

         Building lighting will be provided for security lighting and provide
         400 watt, high pressure sodium fixtures, energized at 277/480 volt with
         photocell control and time clock override. High pressure sodium
         fixtures will have integral ballasts. Fixtures will be pole-mounted in
         parking areas. Provide lighting at sidewalks for pedestrians. Lighting
         at

                                       85

<PAGE>   90


         the parking areas will be in accordance with the latest energy code
         requirements, but will provide a minimum of 0.5 foot candles at the
         remote parking areas.


                                       86

<PAGE>   91

                      DIVISION 16 - ELECTRICAL (Continued)


SECTION 16A - ELECTRICAL WORK  (Continued)


16A-11   EMERGENCY LIGHTING AND POWER SYSTEM

         Provide emergency power for exit lights, emergency lighting and fire
         alarm system. Power source for emergency power shall be wet cell
         batteries located in the electrical rooms or a natural gas fired, roof
         mounted emergency generator as selected by the Landlord. Provide exit
         lights, emergency lights and fire alarm at all common areas as required
         by applicable codes. Exit lights, emergency lights and fire alarm
         distribution at tenant areas are not included.

16A-12   TELEPHONE EQUIPMENT

         Provide two (2) 4" sleeves at each telephone room through the second
         and third floor slabs. Interconnection and telephone equipment will be
         by the telephone company. Telephone interface will be the
         responsibility of the tenant and will be installed in the tenant's
         space.

16A-13   FIRE ALARM SYSTEM

         A local fully addressable fire alarm system with horn/light
         combinations, pull stations and annunciator panel will be provided for
         the base building. The main fire alarm panel and annunciator panel will
         be sized to accommodate the tenant area. Location of horn/lights, pull
         stations and annunciator panel shall be in accordance with applicable
         codes and the local fire department's requirements. Connect to the
         local fire department if available. Double shielded cable will be used.


                                       87

<PAGE>   92

                                   DIVISION 17
                                   EXCLUSIONS

1.    Power wiring for any special equipment or outlets other than those
      specified in these Outline Specifications.

2.    Special floor finishes, other than those previously mentioned.

3.    Special wall finishes, other than those previously mentioned.

4.    Special millwork items, other than those previously mentioned.

5.    Health Department or other regulatory agency requirements resulting from
      tenant's operations unknown to Gutierrez Construction Co., Inc.

6.    Furniture, furnishings, etc.

7.    Security, intercom or sound system.

8.    Vending machines or provisions for such.

9.    Kitchen equipment.

10.   Moveable partitions.

11.   Special exhaust systems.

12.   Underfloor duct systems.

13.   Drinking fountains, other than those specified.

14.   Drywall partitions, including demising walls and painting for tenant
      areas.

15.   Doors, frames and hardware for tenant areas.

16.   Vinyl base for tenant areas.

17.   Power distribution, lights, outlets, light switches, exit signs/lights,
      and emergency lights at tenant areas.

18.   Special modifications required for a day care center, if any.

19.   Sprinkler piping and heads at tenant areas.

20.   HVAC air terminal units, duct work, grilles and diffusers at tenant areas.


                                       88

<PAGE>   93

                                  EXHIBIT "C-2"

                         CERTIFICATE OF FINAL COMPLETION

Project:   Building 3 Bedford Woods Office Park      Lease Date: _________, 2000

Tenant:    RSA Security, Inc.

Location:  174 Middlesex Turnpike                    Date:
           Bedford, Massachusetts

Owner:                              Trade:
Bedford Woods Limited Partnership I


( )   All work has been completed in accordance with Article III of the Lease.

( )   All work has been completed in accordance with Article III of the Lease,
      except for that listed in attached schedule for which a credit has been
      taken.

Final Inspection was made _________________ in the presence of:

Remarks:

Owner must have completed or corrected all punch list items or accepted credit
for unsatisfactory or incomplete work and submitted all Close-out Documents as
listed on Close-out Documents - Record & Transmittal Form.

This is to certify that RSA Security, Inc. will not be held responsible for any
bills, liens, claims or demands in connection with the above noted project. All
workmanship and materials are hereby guaranteed in accordance with stipulations
in the Contract Documents and Lease on Certificate of Substantial Completion.

By:________________________________     By:___________________________________

Title:_____________________________     Title:________________________________

Date:______________________________     Date:_________________________________


NOTE: See also definition of Substantial Completion in Article III of the Lease.


                                       89
<PAGE>   94


                                   EXHIBIT "D"
                              INTENTIONALLY DELETED




<PAGE>   95

                                   EXHIBIT "E"
                              RULES AND REGULATIONS


1.    No curtains, blinds, shades, screens, or signs other than those furnished
      by Landlord shall be attached to, hung in, or used in connection with any
      window or door of the Premises without the prior written consent of the
      Landlord. All interior Tenant signage is at Tenant's expense and must be
      installed or affixed by a contractor first approved by Landlord acting
      reasonably and without delay. The style, size and color of any interior
      signage visible from the exterior of the Premises must also be reasonably
      acceptable to Landlord.

2.    As well as any security (door access) system provided and installed by
      Tenant, as reasonably approved by Landlord, Tenant shall be allowed to
      place additional locks or bolts upon doors and windows within the
      Premises. Tenant recognizes that these additional locks and bolts could
      prove to be a hindrance to Landlord providing building services such as
      cleaning and maintenance. Tenant must, upon the termination of its
      tenancy, remove all additional locks and bolts and restore all original
      door hardware and provide Landlord all Building keys either furnished to
      or otherwise procured by Tenant; and in the event of the loss of any keys
      so furnished, Tenant shall pay to Landlord the reasonable cost thereof.

3.    Canvassing, soliciting and peddling in the Building are prohibited, and
      Tenant shall cooperate to prevent the same.

4.    Tenant shall comply with all reasonably necessary security measures from
      time to time established by Landlord for the Park.

5.    Should Tenant's organization have a non-smoking policy presently in effect
      for their visitors and/or employees or institute such a policy during the
      Term of this Lease, Tenant shall set aside a smoking area within the
      Premises, properly ventilated and/or with smoke filtration units, so as
      not to interfere with any fire protection devices, such as smoke
      detectors, or the quality of air recirculated in the Building's HVAC
      system.

6.    Tenant shall comply with the Park Covenants attached hereto as
      Exhibit "I".


<PAGE>   96


                                   EXHIBIT "F"
                                OPTION TO EXTEND


         The Tenant has the option to extend this Lease for two (2) successive
five (5) year terms ("Extended Term(s)", and separately the "First Extended
Term" and the "Second Extended Term"), the exercise of each of which shall
automatically extend the Term of this Lease without the necessity of additional
documentation, so long as there does not exist any Event of Default hereunder at
such time and so long as Tenant is then leasing at least seventy-five percent
(75%) of the Premises. The option to extend shall be deemed to have been
exercised as to the First Extended Term by Tenant's notification to Landlord
that it elects to exercise its first option to extend at least twelve (12)
months but not more than eighteen (18) months prior to the end of the initial
Term hereunder, and as to the Second Extended Term by Tenant's notification to
Landlord that it elects to exercise its second option to extend at least twelve
(12) months but not more than eighteen (18) months prior to the end of the First
Extended Term. Each Extended Term shall be upon the same terms and conditions as
are set forth in this Lease, including, without limitation, the Tenant's
obligations to pay Operating Cost Reimbursement set forth in Section 4.2.1 and
Real Estate Tax Reimbursement set forth in Section 4.2.2, except that (i) there
shall be no additional option to extend after the termination of the Second
Extended Term or the failure to exercise the first option, whichever shall first
occur, (ii) the annual Fixed Rent for the First Extended Term shall be equal to
the Market Rent (as defined in and determined in accordance with Exhibit P), and
(iii) the annual Fixed Rent for the Second Extended Term shall be equal to the
Market Rent (as defined and determined in accordance with Exhibit P). In no
event, however, shall the annual Fixed Rent and additional rent for the First
Extended Term and for the Second Extended Term be less than the Annual Fixed
Rent and Additional Rent adjusted in accordance with Section 3.8 of this Lease
then in effect as of the last day immediately preceding the First Extended Term
or Second Extended Term, as applicable.



<PAGE>   97

                                   EXHIBIT "G"

                              ESTOPPEL CERTIFICATE


        THIS CERTIFICATE is made to ___________________________ (the "Bank")
with respect to a lease dated _________________ execute by and between
________________________ (the "Landlord") and the undersigned (as "Tenant"),
covering a building (a portion of a building) located in _____________ (the
"Lease"), as amended by (list all amendments):

        The undersigned has been advised that the Bank is about to enter into a
transaction whereby the Bank is making a loan secured by the aforesaid real
estate and the Lease to the undersigned, and under which the Bank may acquire an
ownership interest in such real estate. In connection with this transaction, the
entire interest of the Landlord under the Lease to the undersigned will be
assigned to the Bank. The undersigned acknowledges that the Bank is and will be
relying upon the truth, accuracy and completeness of this letter in proceeding
with the transaction described above.

        The undersigned, for the benefit of the bank, their successors and
assigns, hereby certifies, represents, warrants, agrees and acknowledges that:

        1. The Lease is in full force and effect in accordance with its terms
without modification or amendment except as noted above and the undersigned is
the holder of the Tenant's interest under the Lease.

        2. The undersigned is in possession of all of the Premises described in
the Lease under and pursuant to the Lease and is doing business thereon; and the
Premises are completed as required by the Lease.

        3. The undersigned has no claims or offsets with respect to any of its
obligations as Tenant under the Lease, and neither the undersigned nor the
Landlord is claimed to be in default under the Lease.

        4. The undersigned has not paid any rental or installments thereof in
advance of the due date as set forth in the Lease.

        5. The undersigned has no notice of prior assignment, hypothecation or
pledge of rents of the Lease or the Landlord's interest thereunder or of the
Tenant's interest thereunder.

        6. The term of the Lease has commenced and is presently scheduled to
expire on __________, ____. If there are any rights of extension or renewal
under the terms of the Lease, the same have not, as of the date of this letter,
been exercised.

        7. Until such time as the Bank shall become the Landlord, if the
undersigned should assert a claim that the Landlord has failed to perform an
obligation to the undersigned under the terms of the Lease or otherwise, notice
thereof shall promptly be furnished to the Bank; and the undersigned agrees that
the undersigned will not exercise any rights which the undersigned might
otherwise have on account

<PAGE>   98

of any such failure until notice thereof has been given to the Bank, and the
Bank has had the same opportunity to cure any such failure as the Landlord may
have under the terms of the Lease.

        8. Each of the statements set forth in Paragraphs 1 through 7 are true,
accurate and complete except as follows (state specifically any exception):


DATED

ATTEST:

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

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



                                       2
<PAGE>   99

                                   EXHIBIT "H"

                     TENANT'S CONTRACTORS AND SUBCONTRACTORS
                         MINIMUM INSURANCE REQUIREMENTS

INSURANCE

Before commencing work, the Subcontractor shall procure and maintain at its own
expense until final acceptance of the work, upon all operations and the
operations of its Subcontractors, suppliers or material men on the Project, the
following policies of insurance with Gutierrez Construction Co., Inc., and the
Landlord as additional insured. All policies, including Workers' Compensation,
will include a "Waiver of Rights of Subrogation" against Gutierrez Construction
Co., Inc., and the Landlord.

      a.    WORKER'S COMPENSATION AND EMPLOYERS LIABILITY INSURANCE

            Subcontractor shall provide and maintain Workers' Compensation and
            Employer's Liability Insurance covering all of its employees in
            conformance with laws of the state in which the work and/or Contract
            Documents are to be performed. Such insurance shall not have a limit
            of less than the following:

            Employer's Liability -   $100,000 Each Accident
                                     $500,000 Disease Policy Limit
                                     $100,000 Disease each Employee

      b.    COMMERCIAL GENERAL LIABILITY

            Subcontractor shall procure and maintain coverage to include all
            operations of the insured and/or Contract Documents and coverage for
            all liability assumed with the following limits and extensions of
            coverage.

            Coverage to be on an Occurrence Form

            Coverage to include: Premises and Operations (including X-Explosion,
            C-Collapse and A-Underground Coverages as applicable); Independent
            Contractor's Protective Personal Injury; Contractual; Broad Form
            Property Damage, including Completed Operations with the following
            limits:

            Bodily Injury and Property Damage - $1,000,000 Each Occurrence
                                                $2,000,000 General Aggregate
                                                $1,000,000 Personal Injury

Products and Completed Operations Insurance Aggregate Limit of $2,000,000 shall
be maintained for two (2) years after final payment and Subcontractor shall
continue to provide evidence of such coverage to Gutierrez Construction Co.,
Inc., and the Landlord on an annual basis during the two year period.

      c.    BUSINESS AUTOMOBILE LIABILITY

<PAGE>   100

            Subcontractor shall procure and maintain Business Automobile
            Liability Insurance covering owned, non-owned and hired motor
            vehicles with the following combined single limits:

            Bodily Injury and Property Damage - $1,000,000 Each Occurrence
            (C.S.L.)

      d.    UMBRELLA LIABILITY

Subcontractor shall procure and maintain an Umbrella Liability Policy with
limits of $2,000,000.

<PAGE>   101

                                   EXHIBIT "I"

                                 PARK COVENANTS

      Landlord agrees with Tenant to enforce, or cause to be enforced, these
Park Covenants with all due diligence to preserve the quality and appearance of
the Park.

      The Lot is approximately 31.16 acres and is located in an approximately
seventy-nine (79) acre office/research and development park shown on the Plan of
the Park attached hereto as part of Exhibit A and more particularly described
therein and elsewhere in this Lease, as the same, including without limitation
the Common Areas of the Park, may be amended by Landlord from time to time in
accordance with and subject to the provisions of Section 2.1 of this Lease.

      All lots of land comprising the Park (which lots, including without
limitations the Lot, are individually called the "Parcel" and collectively the
"Parcels") are subject to the following restrictions which shall bind Bedford
Woods Limited Partnership I (collectively "Grantor") as original owner of the
Park and its successors in title.

      A. All parcels shall have facilities for parking, loading and unloading
sufficient to serve any uses of the Parcels without using adjacent streets for
such purpose. On-street parking shall be prohibited. All parking, trucking and
vehicular maneuvering areas for a Parcel shall be contained within such Parcel.

      B.    No exterior loading platforms shall be visible from any primary way
or proposed primary way serving the Park. Screening and planting may be used for
this purpose.

      C.    No open or outside storage shall be done on any Parcel, other than
normal and customary trash compactors and containers on locations to be
reasonably approved by Landlord in advance.

      D.    Signs shall conform to the sign ordinances of the Town of Bedford.
Any variance from such ordinance granted by the Town of Bedford must also be
approved by Grantor in the manner provided below in Section I.

      E.    No condition or use of any Parcel will be permitted which is
objectionable by reason of noise, odor, vibration, smoke, radiation, the
hazardous nature of the use, or the violation of environmental laws or
regulations adopted by the Town of Bedford, the Commonwealth of Massachusetts,
the Federal Government or any Court.

      F.    All utilities serving a Parcel shall be placed underground, unless
prohibited by the utility company. Any exterior lighting on a Parcel shall
either be indirect or of such controlled focus and intensity as not to disturb
street traffic or the occupancy of any adjacent Parcel.

      G.    The exterior appearance of any buildings in the Park, including
landscaping thereon, shall be kept neat and orderly and free from litter.

      H.    No building, exterior sign, fence, wall, exterior lighting or other
structure shall be erected or allowed to maintain on any portion of the Park or
exterior structural alteration or addition made,

<PAGE>   102


except pursuant to plans approved in writing by Grantor as to landscaping,
parking and architectural conformity with existing buildings in the Park.

      I.    The Grantor may from time to time by written instrument in
recordable form grant variance from any one or more of these restrictions
(except restriction H for which variances may not be granted) where the Grantor
reasonably determines that the variance can be granted without substantial
detriment to the intent and purpose of the restrictions and without substantial
detriment to the Land, and portions of the Park theretofore built upon. If
Tenant is occupying seventy-five percent (75%) or more of both this Building and
Building 4 in the Park then variances from these restrictions shall require the
consent of Tenant which consent shall not be unreasonably withheld, conditioned
or delayed. Failure by Tenant to respond in writing to a proposed variance
request within ten (10) days of receipt of such variance request shall be deemed
acceptance by Tenant of such variance request.

      J.    Written approval by the Grantor as to any buildings, signs,
structures, alterations, additions and landscaping approved by Grantor in good
faith shall be conclusive evidence of compliance with these restrictions. The
Grantor agrees to furnish to any grantee such written instruments in recordable
form as may reasonably be requested by the grantee as evidence of such
compliance.

      K.    Building 3 and Building 4 (i.e. those buildings closest to Noreen
Drive, Bedford, Massachusetts) shall install and maintain as operable all
interior non-emergency lighting on those sides of the Building 3 and Building 4
which face Noreen Drive (i.e. the Northwest) and in the case of Building 4 the
Southwest, on motion detector shutoff switches which turn off the lights in
those offices or spaces when motion is not detected therein.

      L.    The term "Grantor", as herein used, shall mean Bedford Woods Limited
Partnership I and any of its successors in title to whom the Grantor has
expressly granted of record the rights to enforce these restrictions.

      This property is subject to a Special Permit from the Town of Bedford,
Massachusetts for increased number of parking spaces. The Landlord and Tenant
agree to cooperatively participate in, and actively support, Landlord's and/or
the Park's Transportation Demand Management Plan wherever possible to achieve
the Park's goal of peak hour traffic reduction. Tenant shall reimburse Landlord
for its pro rata share of Landlord's Transportation Demand Management Plan
expenses.

      This Plan may include such services as:

            *     Access GIS/Rideshare to assist in matching interested
                  employees into car-pools;

            *     Provide a "Guaranteed Ride" program which provides a back-up
                  in the event of an emergency;

            *     Promotional events at their facilities to distribute
                  transportation information and answer questions;

            *     Operate a "transportation store" to provide up-to-date
                  information on transit schedules, services, and fares;

                                       2
<PAGE>   103

            *     Organize van-pools;

            *     Work with state agencies including MassHighway, EOTC, CARAVAN
                  Commuters, or others, as necessary on transportation matters;
                  and

            *     Implement preferential parking for rideshares.


                                       3

<PAGE>   104

                                   EXHIBIT "J"


                            LESSEE'S LEASE STATEMENT
                                       AND
             SUBORDINATION, NON-DISTURBANCE AND ATTORNMENT AGREEMENT

      THIS AGREEMENT is made and entered into as of this _____ day of November,
2000, by and among WELLS FARGO BANK, NATIONAL ASSOCIATION, a national banking
association (hereinafter called the "Lender"), RSA SECURITY, INC., a
________________ corporation (hereinafter called the "Tenant"), and BEDFORD
WOODS LIMITED PARTNERSHIP I (hereinafter called the "Landlord").

                                   WITNESSETH:

      WHEREAS, Landlord owns certain real property commonly known as Building
Three of Bedford Woods, and located in Bedford, Middlesex County, Massachusetts,
and more particularly described in Exhibit "A" attached hereto and made a part
hereof (said property being hereinafter called the "Property"); and

      WHEREAS, Landlord and Tenant made and entered into that certain Lease
dated as of the _____ day of November, 2000, with respect to certain premises
located on the Property constituting the Premises therein described (said Lease
being hereinafter called the "Lease", and said premises being hereinafter called
the "Leased Premises"); all capitalized terms used herein and not otherwise
defined shall have the same meaning as set forth in the Lease; and

      WHEREAS, Landlord has entered into and delivered that certain Construction
Mortgage and Security Agreement in favor of Lender recorded in the Middlesex
North district Registry of Deeds on _____________, 2000 as Instrument No.
_____________ prior to the recording of this Agreement (said Construction
Mortgage and Security Agreement being hereinafter called the "Mortgage"),
granting a lien on the Property to secure the payment of the indebtedness
described in the Mortgage; and

      WHEREAS, on or about the date hereof, Landlord has entered into and
delivered that certain Assignment of Leases and Rents in favor of Lender
recorded in the Middlesex North District Registry of Deeds on
__________________, 2000 as Instrument No. ________ prior to the recording of
this Agreement (said Assignment of Leases and Rents being hereinafter called the
"Assignment of Leases"), assigning all of Landlord's right, title and interest
as Lessor under the Lease to further secure the indebtedness described in the
Mortgage; and

      WHEREAS, the Mortgage and the Assignment of Leases secure the repayment of
a loan from Lender to Landlord in the principal amount of $______________ (the
"Loan") as evidenced by that certain Promissory Note of Landlord to Lender dated
_______________, 2000 (the "Note"); and

      WHEREAS, the proceeds of the Note are being advanced pursuant to the terms
of that certain Construction Loan Agreement between Landlord and Lender dated
____________, 2000 (the "Construction Loan Agreement"): the Note, Mortgage,
Assignment of Leases, Construction Loan

<PAGE>   105

Agreement and all other documents extended in connection with the Loan are
sometimes hereinafter collectively referred to as the "Loan Documents"; and

      WHEREAS, The Gutierrez Company, The Gutierrez Construction Co., Inc.,
Arturo J. Gutierrez and John A. Cataldo (collectively, the "Guarantors") have
executed and delivered to Lender certain guaranties in connection with the Loan;
and

      WHEREAS, the Lender represents that it is the sole holder of the Mortgage
and the Note and other loan documents secured thereby; and

      WHEREAS, the parties hereto desire to enter into this Non-Disturbance,
Attornment and Subordination Agreement;

      NOW, THEREFORE, for and in consideration of the mutual covenants
hereinafter set forth and other good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, Lender, Tenant and Landlord hereby
covenant and agree as follows:

      1.    ESTOPPEL - Tenant hereby certifies to Lender that, as of the date of
this Agreement: (i) the Lease, as described above, is the true, correct and
complete Lease and has not been modified or amended and constitutes the entire
agreement between Landlord and Tenant, (ii) to the best of Tenant's knowledge,
there are no defaults of Landlord under the Lease and there are no existing
circumstances which with the passage of time, or giving of notice, or both,
would give rise to default under the Lease and/or allow Tenant to terminate the
Lease, (iii) Tenant is satisfied with all of the work done by and required of
Landlord to date, such work has been done in accordance with plans and
specifications approved by Tenant, and as of the date hereof Tenant is not aware
of any defect in the work or has not rejected any of the work done by Landlord
on the Leased Premises (only includable if Tenant agrees with, after work is
completed), (iv) that no rent under the Lease has been paid more than thirty
(30) days in advance of its due date; (v) that the Tenant, as of this date, has
no charge, lien or claim of offset under the Lease or otherwise, against rents
or other charges due to become due thereunder; and (vi) that Tenant has not
assigned any of its rights under the Lease nor has Tenant sublet any portion of
the Demised Premises to any other party. If this Agreement is being delivered
prior to completion of all of Landlord's Work (as such term is defined in the
Lease) on the Leased Premises, Tenant agrees that, promptly after request of the
Lender therefor, it will provide an estoppel certificate to Lender following
completion of such work indicating whether Tenant has accepted the work and
begun payment of rent.

      2.    NON-DISTURBANCE - Lender agrees that if Lender comes into possession
of or acquires title to all or any part of the Leased Premises or the Lot (as
defined in the Lease) as a result of foreclosure or other enforcement of the
Mortgage or the Assignment of Leases, or both, then so long as no default under
the Lease by Tenant exists and continues beyond the expiration of all applicable
cure periods (after notice, if any, required by the Lease) as would entitle the
Landlord under the Lease to terminate the Lease or would cause, without any
further action on the part of such Landlord, the termination of the Lease, the
Lease shall not be terminated, nor shall Tenant's use, possession or enjoyment
of the Leased Premises and appurtenant rights and interests or rights under the
Lease be interfered with. Following a foreclosure or other action or proceeding
in the nature of foreclosure instituted under or in connection with the Mortgage
or the Assignment of Leases, or the acquisition of title to the Leased Premises,
the person or entity acquiring the interest of the Landlord under the Lease as a
result of any such action or

                                       2

<PAGE>   106

proceeding or deed in lieu of any such action or proceeding (hereinafter called
the "Purchaser") or Lender if Lender takes possession of the Property shall have
all rights and obligations of Landlord under the Lease, except as expressly
otherwise set forth herein, provided, however, that neither the Purchaser nor
the Lender shall be (a) liable for any act or omission of any prior lessor under
the Lease provided that nothing herein shall (i) relieve such Purchaser or
Lender from curing any continuing non-monetary defaults of Landlord after
receipt of requisite notices from Tenant, all in accordance with the Lease or
(ii) impair the Tenant's offset or abatement rights as provided in clause 2(c)
below with respect to any continuing monetary defaults of Landlord under the
Lease; or (b) liable for the return of any security deposit which Tenant under
the Lease has paid under the Lease unless such security deposit is received by
Lender; or (c) subject to any offsets, abatements or defenses which the Tenant
under the Lease might have against any prior lessor under the Lease unless
Lender has received prior written notice of the offset, abatement or defense and
opportunity to cure the same in accordance with Paragraph 9 below; or (d) bound
by any base rent, or any other payments which the Tenant under the Lease might
have paid for more than the current month to any prior lessor under the Lease;
or (e) bound by any amendment or modification of the Lease made without Lender's
prior written consent (Lender hereby agreeing not to unreasonably withhold or
delay its consent); or (f) bound by any assignment or sublease of the Tenant's
interest in the Lease made without obtaining Lender's prior written consent
(such consent not to be unreasonably withheld or delayed), except where the
consent of the Landlord is not required pursuant to the provisions of Section
6.1.6 of the Lease; or (g) personally liable for any default under the Lease or
any covenant or obligation on its part to be performed thereunder as Landlord,
it being acknowledged that Tenant's sole remedy in the event of such default
shall be to proceed against Purchaser's or Lender's interest in the Property and
the rents, or other proceeds arising therefrom.

         3. TENANT'S ELECTIONS - Notwithstanding any other provision to the
contrary contained in the Lease, if prior to the substantial completion of the
Landlord's Work or Tenant's Work (as defined in the first paragraph of Section
3.1 and Section 3.1.1 of the Lease), Lender accelerates the Note and demands
payment of same, Lender then will give written notice of such acceleration and
demand (the "Demand Notice") to Tenant. Upon receipt by Tenant of the Demand
Notice, in a written notice (the "Election Notice") to Lender, provided a copy
thereof is simultaneously given by Tenant to Landlord and further provided
Lender receives the Election Notice within sixty (60) days of Tenant's receipt
of the Demand Notice (the "Election Period"), Tenant may elect the option set
forth below. Lender agrees not to acquire title to or take possession of the
Leased Premises (a) during the Election Period and (b) if Tenant exercises its
election below, for a period of forty-five (45) days after Lender receives the
Election Notice (the "Standstill Period"). If Tenant shall fail to deliver to
Lender the Election Notice prior to the expiration of the Election Period, then
all rights and obligations of Tenant and Lender under this Paragraph 3 shall
automatically cease and terminate.

         In the Election Notice, Tenant may elect to purchase from Lender all of
Lender's right, title and interest in and to the Loan Documents, for a sum equal
to the total amount then due and owing to Lender thereunder (the "Sale") as of
the closing (the "Sale Closing") of the Sale, including, but not limited to, all
outstanding principal, interest, late fees, charges and attorney's fees due
under the Loan Documents as of the Sale Closing, together with all fees, costs
and expenses incurred by Lender in connection with the preparation of all
documents reasonably required by Lender to evidence the Sale (collectively, the
"Obligations"), which documents shall be in form and substance reasonably
satisfactory to Lender and which shall be without recourse to Lender and shall
not contain any warranties or representations other than a representation from
Lender to Tenant that (x) it owns the Loan Documents, (y) the Loan


                                       3

<PAGE>   107

Documents are free and clear of any liens or any other person's or entity's
interest therein and (z) Lender has all necessary power and authority without
need for consent from any other person or entity to sell the Loan Documents or
has obtained all necessary consents therefor; PROVIDED, HOWEVER, Tenant's right
to purchase the Loan Documents hereunder automatically shall expire and Lender
no longer shall have any obligations to Tenant under this clause (i) or clause
(ii) below if the Sale Closing and payment to Lender of the Obligations in
immediately available funds have not occurred on or before forty-five (45) days
after Lender receives the Election Notice.

         4. LENDER'S ELECTIONS - In the event that Lender acquires title to or
possession of all or any part of the Leased Premises at any time after the
expiration of the Standstill Period, whether pursuant to a foreclosure
proceeding or otherwise, then within thirty (30) days thereafter, the Lender may
elect to deliver a written notice to the Tenant stating that either (i) the
Lender intends to perform the construction obligations of the Landlord set forth
in Article 3 of the Lease (the "Construction Obligations"), or (ii) the Lender
does not intend to perform the Construction Obligations. A notice delivered by
the Lender pursuant to clause (i) is referred to herein as an "Opt-In
Construction Notice" and a notice delivered by the Lender pursuant to clause
(ii) is referred to herein as an "Opt-Out Construction Notice".

         In the event that Lender does not deliver either an Opt-Out
Construction Notice or an Opt-In Construction Notice to the Tenant within said
thirty (30) days after acquisition of title or possession, then Tenant may elect
to deliver a written request (a "Construction Confirmation Request") to the
Lender requesting that Lender deliver either an Opt-Out Construction Notice or
an Opt-In Construction Notice.

         If either (a) Lender delivers an Opt-Out Construction Notice to Tenant,
as aforesaid, or (b) Lender does not deliver an Opt-In Construction Notice to
Tenant by not later than thirty (30) days after receipt of Tenant's Construction
Confirmation Request, then Lender shall not be obligated to perform the
Construction Obligations in accordance with the terms and provisions of the
Lease. If Lender delivers an Opt-In Construction Notice as aforesaid, then
Lender shall be obligated to perform the Construction Obligations in accordance
with the terms and provisions of the Lease. If Lender timely delivers an Opt-Out
Construction Notice to Tenant by not later than thirty (30) days after receipt
of Tenant's Construction Confirmation Request as aforesaid, or Lender does not
deliver an Opt-In Construction Notice to Tenant by not later than thirty (30)
days of its receipt of Tenant's Construction Confirmation Request, then (a)
Lender shall have no obligation to perform the Construction Obligations, and (b)
Tenant may elect to terminate the Lease by providing written notice of such
election to Lender. If Tenant elects to terminate the Lease, the Lease shall be
terminated effective as of the date specified in Tenant's notice. Thereafter,
the Lease shall be null and void and of no further force or effect, and neither
the Tenant nor the Lender shall have any further liabilities or obligations
thereunder.

         If (a) Lender sells, conveys, assigns, pledges or transfers its
interest in the Loan, or (b) Lender sells the Leased Premises, or any part
thereof, at a foreclosure sale, or (c) if Lender acquires title to the Leased
Premises and subsequently conveys the Leased Premises, then, in any such event,
concurrently with such transaction, Lender shall transfer, assign and convey all
right, title and interest of the Lender in and to the Security Deposit then held
by it, if applicable, to such purchaser, assignee, or transferee.
Notwithstanding anything to the contrary contained in this Section, if Lender so
transfers, assigns or conveys all right, title and interest of the Lender in and
to the Security Deposit, if applicable, as


                                       4
<PAGE>   108

aforesaid, then Lender shall have no liability for the return of the Security
Deposit.

         5. ATTORNMENT - Unless the Lease is terminated in accordance with
Paragraphs 2 or 4 of this Agreement or in accordance with the terms of the
Lease, if the interests of the Landlord under the Lease shall be transferred by
reason of the exercise of power of sale contained in the Mortgage (if
applicable), or by any foreclosure or other proceeding for enforcement of the
Mortgage, or by deed in lieu of foreclosure or such other proceeding, or if
Lender takes possession of the Property pursuant to any provisions of the
Mortgage, Tenant shall be bound to the Purchaser or Lender, as the case may be,
under all of the terms, covenants and conditions of the Lease for the balance of
the term thereof and any extensions or renewals thereof which may be effected in
accordance with any option therefor in the Leases with the same force and effect
as if the Purchaser or Lender were the lessor under the Lease, and Tenant, as
Lessee under the Lease, does hereby agree to attorn to the Purchaser and Lender
if it takes possession of the Property, as its lessor under the Lease. Such
attornment shall be effective and self-operative without the execution of any
further instruments upon succession by Purchaser to the interest of the lessor
under the lease or the taking of possession of the Property by Lender.
Nevertheless, Tenant shall, from time to time, execute and deliver such
instruments evidencing such attornment as Purchaser or Lender may reasonably
require. The respective rights and obligations of Purchaser, Lender and of the
lessee under the Lease upon such attornment, to the extent of the then remaining
balance of the term of the Lease and any extensions and renewals, shall be and
are the same as now set forth in the Lease, except as otherwise expressly
provided herein.

         6. SUBORDINATION - Subject to the provisions of this Agreement, Tenant
hereby subordinates all of its right, title and interest as Lessee under the
Lease to the right, title and interest of Lender under the Mortgage, and Tenant
further agrees that the Lease now is and shall at all times continue to be
subject and subordinate in each and every respect to the Mortgage and to any and
all increases, renewals, modifications, extensions, substitutions, replacements
and/or consolidations of the Mortgage and to all sums secured thereby with the
same force and effect as if the Mortgage had been executed, delivered and
recorded prior to the execution and delivery of the Lease. Notwithstanding the
foregoing, such subordination shall not decrease or impair the rights of Tenant
under the Lease, except as specifically set forth herein.

         7. OTHER CONDITIONS - Notwithstanding anything to the contrary
contained in this Agreement or in the Lease, Lender, Tenant and Landlord agree
that to the extent required by the Lease, and provided that (i) Tenant has not
defaulted in the payment of rent or other charges under the Lease, (ii) Landlord
has not defaulted in the payment of debt service or other payments under the
loan documents and (iii) neither Landlord nor Tenant has filed a voluntary
petition in bankruptcy under Title 11 of the United States Code or had an order
for relief issued against it and not dismissed within thirty (30) days of
issuance or has filed any petition or answer seeking or acquiescing in any
reorganization, arrangement, composition, readjustment, liquidation, dissolution
or similar relief for itself under any present of future federal, state or other
law or regulation relating to bankruptcy, insolvency or other relief of debtors
or consented to or acquiesced in the appointment of any custodian, trustee,
receiver, conservator or liquidator for it or all or any substantial part of its
property or made an assignment of a substantial portion of its assets for the
benefit of creditors (or if any of the foregoing has occurred only with respect
to Landlord and Tenant has exercised its election under clause (ii) of Paragraph
3 above by giving Lender the Election Notice required therein), then in the
event of an insured casualty to the Leased Premises, and if Landlord satisfies
the conditions provided for hereafter, Lender shall hold the

                                       5
<PAGE>   109


balance of any casualty and rental interruption proceeds after proof and
adjustment and shall use such funds for the following purposes: (x) to pay costs
and obligations secured by the Mortgage (the "Secured Obligations") as such
become due during the course of reconstruction or repair of the Leased Premises,
(y) to reimburse Landlord, in accordance with the terms and conditions set forth
below, for the costs of reconstruction or repair of the Leased Premises, and (z)
upon completion of such reconstruction or repair, to apply any excess to the
payment of the Secured Obligations. Such funds shall be made available as
provided above and as provided in Section 4.8(b) of the Mortgage upon the
Landlord's prior satisfaction of such conditions as the Lender may reasonably
establish with respect thereto (each of which must be complied with in a manner
reasonably satisfactory to the Lender, with all documents, instruments,
agreements, or evidence to be in form and substance satisfactory to the Lender),
within sixty (60) days of the date of such damage or destruction to the Leased
Premises, including without limitation, the following (hereinafter referred to
as the "Funding Requirements"):

       (i)    delivery of estoppel certificate(s) or other satisfactory evidence
              that the Lease remains in full force and effect and will remain in
              full force and effect after such repair and restoration, without
              any right of termination or cancellation during the projected
              course of said repair or restoration;

       (ii)   delivery of plans and specifications, construction budget,
              construction contract, and construction schedule for such repair
              and restoration, satisfactory to Lender;

       (iii)  delivery of evidence of compliance with all applicable state,
              federal and local laws, ordinances and regulations relating to
              such repair and restoration, and the issuance of all required
              permits, licenses and approvals relative thereto;

       (iv)   delivery of evidence of the availability of any funds necessary to
              complete such repairs and restoration in excess of such proceeds,
              which funds, at the request of the Lender, shall be deposited with
              the Lender to be disbursed with such proceeds;

       (v)    builder's all risk insurance;

       (vi)   rent loss insurance sufficient to pay all operating costs and debt
              service confirmed by the insurer to be available for the period of
              repair and restoration;

       (vii)  evidence that the insurer under such policies of fire or other
              casualty insurance does not assert any defense to payment under
              such policies against Lender, Landlord or any tenant of the Leased
              Premises;

       (viii) execution of any documentation deemed reasonably necessary by the
              Lender to provide for the disbursement of such funds in a manner
              typical to a construction loan;

       (ix)   delivery of evidence that the repair or restoration can be
              completed prior to the then applicable maturity date of the note;

       (x)    Landlord delivers to Lender a written undertaking to expeditiously
              commence and to satisfactorily complete with due diligence the
              necessary restoration;


                                       6
<PAGE>   110

       (xi)   compliance of such other reasonable non-financial terms and
              conditions customary for construction loans of the size and scope
              involved with such repairs and restoration; and

       (xii)  such other requirements as provided in Section 4.8(a) of the
              Mortgage provided that such requirements do not include the
              execution of a separate guaranty of completion by Tenant for the
              purpose of making funds available for restoration under this
              Paragraph 6.

       8.     ASSIGNMENT OF LEASES - Tenant hereby acknowledges that all of
Landlord's right, title and interest as Lessor under the Lease is being duly
assigned to Lender pursuant to the terms of the Assignment of Leases, and that
pursuant to the terms thereof, all rental payments under the Lease shall
continue to be paid to Landlord in accordance with the terms of the Lease unless
and until Tenant is otherwise notified in writing by Lender. Upon receipt of any
such written notice from Lender, Tenant covenants and agrees to make payment of
all rental payments then due or to become due under the Lease directly to Lender
or to Lender's agent designated in such notice and to continue to do so until
otherwise notified in writing by Lender. Landlord hereby irrevocably directs and
authorizes Tenant to make rental payments directly to Lender following receipt
of such notice and covenants and agrees that Tenant shall have the right to rely
on such notice without any obligation to inquire as to whether any default
exists under the Mortgage or the Assignment of Leases or the indebtedness
secured thereby, and notwithstanding any notice of claim of Landlord to the
contrary, that Landlord shall have no right or claim against Tenant for or by
reason of any rental payments made by Tenant to Lender following receipt of such
notice, and all such payments by Tenant to Lender are fully authorized by
Landlord and treated for all purposes as payments of Fixed or Additional Rent
under the Lease. Except as otherwise specifically set forth in the Lease, Tenant
further acknowledges and agrees: (a) that under the provisions of the Assignment
of Leases, the Lease cannot be terminated (nor can Landlord accept any surrender
of the Lease) or modified in any of its terms, or consent be given to the waiver
or release of Tenant from the performance or observance of any obligation under
the Lease without the prior written consent of Lender, and without such consent,
no rent may be collected or accepted by Landlord more than one month in advance;
and (b) that the interest of Landlord as Lessor under the Lease has been
assigned to Lender for the purposes specified in the Assignment of Leases, and
Lender assumes no duty, liability or obligation under the Lease, except only
under the circumstances, terms and conditions specifically set forth in the
Assignment of Leases or this Agreement.

       9.     NOTICE OF DEFAULT BY LESSOR - Tenant, as Lessee under the Lease,
hereby covenants and agrees to give Lender written notice properly specifying
wherein the Lessor under the Lease has failed to perform any of the covenants or
obligations of the Lessor under the Lease simultaneously with the giving of any
notice of such default to the Lessor under the provisions of the Lease. Tenant
agrees that Lender shall have the right, but not the obligation, within thirty
(30) days after receipt by Lender of such notice (or, with respect to
non-monetary defaults only, within such additional time as is reasonably
required to correct any such default) to correct or remedy, or cause to be
corrected or remedied, each such default before the Lessee under the Lease may
take any action under the Lease by reason of such default; provided, however, in
no event shall such time extend for more than sixty (60) days after Tenant
provides such notice to Lender, except if Lender has commenced to cure any such
non-monetary default under the Lease (which shall in no event include
foreclosure or exercise of other remedies available under the Mortgage) within
thirty (30) days after such written notice to Lender and is diligently
proceeding to cure such default and such non-monetary default cannot be cured
within sixty (60) days

                                       7

<PAGE>   111

despite such diligent efforts to cure on the part of Lender, in which event such
time period may be extended for such additional period as may be necessary to
complete the curing of such non-monetary default with diligence and continuity;
and provided further such cure period shall not affect the right of Tenant to
terminate the lease (i) under Section 2.4 of the Lease ("Early Termination
Opinion"), (ii) under Paragraph 3.2 of the Lease if the Leased Premises are not
deemed ready for occupancy by the "Outside Delivery Date" (as defined therein)
or (iii) in the event Lender has delivered to Tenant an Opt-Out Construction
Notice pursuant to Paragraph 4 above. Such notices to Lender shall be delivered
in duplicate in writing by registered or certified mail, return receipt
requested, or by depositing the same with an overnight commercial courier (such
as Federal Express) or by hand delivery to:

                Wells Fargo Bank, National Association
                121 High Street, 5th Floor
                Boston, MA 02110
                Attention:  Kimberly A Dail

With copy to:   Wells Fargo Bank, National Association
                Real Estate Group
                420 Montgomery Street, Sixth Floor
                San Francisco, California 94111
                Attention:  Chief Credit Officer - Real Estate Group

                and

                Wells Fargo Bank, National Association
                Real Estate Group
                Suite 420
                2020 K Street, N.W.
                Washington, D.C. 20006
                Attention:  Manager, Loan Administration Department

or to such other address as the Lender shall have designated to Tenant by giving
written notice to Tenant at:

                RSA Security, Inc.
                20 Crosby Drive
                Bedford, Massachusetts  01730


                                       8

<PAGE>   112



With copy to:  Robert Tuchmann, Esq.
               Hall & Dorr LLP
               60 State Street
               Boston, Massachusetts  02109

or to such other address as may be designated by written notice from Tenant to
Lender.

         10. NO FURTHER SUBORDINATION - Except as expressly provided to the
contrary in Paragraph 6 hereof, Landlord and Tenant covenant and agree with
Lender that there shall be no further subordination of the interest of Lessee
under the Lease to any lender or to any other party without first obtaining the
prior written consent of Lender. Any attempt to effect a further subordination
of Lessee's interest under the Lease without first obtaining the first written
consent of Lender shall be null and void.

         11. CONSENT - Lender hereby consents to the Lease.

         12. TRADE FIXTURES OR EQUIPMENT - The lien of the Mortgage does not
encumber any trade fixtures or equipment or other personal property used and
paid for by Tenant in its business on the Property.

         13. AS TO LANDLORD AND TENANT - As between Landlord and Tenant,
Landlord and Tenant covenant and agree that nothing herein contained, nor
anything done pursuant to the provisions hereof, shall be deemed or construed to
modify the Lease.

         14. AS TO LANDLORD AND LENDER - As between Landlord and Lender,
Landlord and Lender covenant and agree that nothing herein contained, nor
anything done pursuant to the provisions hereof, shall be deemed or construed to
modify the Mortgage or the Assignment of Leases.

         15. TITLE OF PARAGRAPHS - The titles of the paragraphs of this
agreement are for convenience and reference only, and the words contained
therein shall in no way be held to explain, modify, amplify or aid in the
interpretation, construction or meaning of the provisions of this agreement.

         16. GOVERNING, LAW - This agreement shall be governed by and construed
in accordance with the laws of the Commonwealth of Massachusetts.

         17. PROVISIONS BINDING - The terms and provisions hereof shall be
binding upon and shall inure to the benefit of the heirs, executors,
administrators, successors and permitted assigns, respectively, of Lender,
Tenant and Landlord. The reference contained to successors and assigns of Tenant
is not intended to constitute and does not constitute a consent by Landlord or
Lender to an assignment by Tenant where such consent is required under the
Lease, but has reference only to those instances in which the Lessor under the
Lease and Lender shall have given written consent to a particular assignment by
Tenant thereunder where such consent is required under the Lease. In the event
of a conflict between the provisions of this Agreement and the provisions of the
Lease, the provisions of this Agreement shall prevail.


                                       9
<PAGE>   113

         In the event of any transfer of the Mortgage or the note secured
thereby, the Lender shall transfer and deliver to the transferee any security
deposit under the Lease held by Lender or its agent, and provided the transferee
assumes the obligations of Lender hereunder or otherwise recognizes the
provisions hereof by written instrument delivered to Tenant, Lender shall
thereupon become freed and relieved of all covenants and obligations of the
Lender hereunder, except with respect to any breaches of this Agreement as shall
have theretofore occurred.

         18. COUNTERPARTS - This Agreement may be executed in two or more
counterparts, each of which shall be deemed an original, but all of which
together shall constitute one and the same instrument.

         19. MODIFICATION - This Agreement may not be modified orally or in any
manner other than by an agreement in writing signed by the parties hereto or
their respective successors in interest.

         20. INFORMATION. So long as the Loan is outstanding, Tenant covenants
to provide Lender with all information, including, but not limited to evidence
of payment of taxes and insurance (if Tenant is obligated for such payments
under the Lease) to which the Landlord may be entitled under the Lease.

         21. INSPECTIONS. So long as the Loan is outstanding, Lender or its
designee may enter upon the Property at all reasonable times, upon reasonable
notice to Tenant, to visit or inspect the Property and discuss the affairs,
finances and accounts of Tenant applicable to the Property or the Lease at such
reasonable times as Lender or its designee may request.

         22. ENFORCEABILITY. Each of Tenant, Landlord and Mortgagee hereby
represents and warrants that the Lease and this Agreement have been duly
authorized, executed and delivered by such party and constitute legal, valid and
binding instruments, enforceable against such party in accordance with their
respective terms, except as such terms may be limited by bankruptcy, insolvency
or similar laws affecting creditors' rights generally.

         IN WITNESS WHEREOF, the parties have executed this Agreement as an
instrument under seal and hereunto set their respective hands and seals as of
the day, month and year first above written.

                                        LENDER:

                                        WELLS FARGO BANK, NATIONAL ASSOCIATION



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


                                       10
<PAGE>   114


                                     TENANT:

                                     RSA SECURITY, INC.



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


                                     LANDLORD:

                                     BEDFORD WOODS LIMITED PARTNERSHIP I
                                     By:  THE GUTIERREZ COMPANY,
                                            its general partner



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


STATE OF
         --------------------------

                County, SS                                                , 2000
---------------                                          -----------------


Then personally appeared before me ___________________, the _________________ of
WELLS FARGO BANK, NATIONAL ASSOCIATION, to me personally known, who I am
satisfied signed the foregoing instrument, and who did acknowledge under oath
that he/she signed and delivered the same in his/her capacity as
______________________, and that the foregoing instrument is his/her free act
and deed and the free act and deed of such WELLS FARGO BANK, NATIONAL
ASSOCIATION.


                                         --------------------------------------
                                         Notary Public
                                         My Commission Expires:



                                       11

<PAGE>   115


STATE OF
         --------------------------

                County, SS                                                , 2000
---------------                                          -----------------


Then personally appeared before me ________________________, the
____________________ of RSA SECURITY, INC., to me personally known, who I am
satisfied signed the foregoing instrument, and who did acknowledge under oath
that he/she signed and delivered the same in his/her capacity as
__________________________, and that the foregoing instrument is his/her free
act and deed and the free act and deed of such RSA SECURITY, INC.



                                         --------------------------------------
                                         Notary Public
                                         My Commission Expires:



                                       12

<PAGE>   116

                                   EXHIBIT "L"

                         DEFINITION OF COST OF THE WORK

REIMBURSABLE COSTS:

The following 18 numbered items shall be used to determine and calculate the
Cost of the Work:

1.     The term Cost of the Work shall mean costs necessarily incurred and paid
       by the Contractor in the proper performance of the Work. Such costs shall
       be at rates not higher than the standard paid in the greater Boston area
       and shall include the items set forth below. The Contractor, as
       hereinafter defined, agrees to solicit bids from at least three (3)
       subcontractors on each major trade for all items costing more than
       $50,000.00. Landlord shall have the right to select the subcontractors to
       bid on the Tenant Work; however Tenant may propose qualified
       subcontractors to participate in the competitive bidding process,
       provided that any such subcontractors must be approved by Landlord in its
       reasonable judgment.

2.     Wages paid for labor in the direct employ of Gutierrez Construction Co.,
       Inc. ("Contractor") in the performance of the Work under applicable
       collective bargaining agreements, or under a salary or wage schedule
       agreed upon by the Landlord, and Contractor, and including such welfare
       or other benefits, if any, as may be payable with respect thereto.

3.     Salaries of Contractor's personnel when stationed at the field office, in
       whatever capacity employed, and a proportionate share of the project
       manager and construction managers' salaries, whether at the job site or
       in the main office. Personnel engaged at shops or on the road in
       expediting the production or transportation of materials or equipment
       shall be considered as stationed at the field office and their salaries
       paid for that portions of their time spent on the work.

4.     Cost of contributions, assessments or taxes incurred during the
       performance of the work for such items as unemployment compensation and
       social security, insofar as such cost is based on wages, salaries or
       other remuneration paid to employees of the Contractor and included in
       the Cost of the Work under subsections 2 and 3.

5.     Costs of all materials, supplies and equipment incorporated in the work,
       including costs of transportation thereof.

6.     Payments made by the Contractor to subcontractors for work performed
       pursuant to subcontracts.

7.     Cost, including transportation and maintenance, of all materials,
       supplies, equipment, temporary facilities and hand tools not owned by the
       workers, which are consumed in the performance of the work, and cost less
       salvage value on such items used by not consumed which remain the
       property of the Contractor.


<PAGE>   117


8.     Rental charges of all necessary machinery and equipment, exclusive of
       hand tools, used at the site in performance of the work, whether rented
       from the Contractor or others including installation, minor repairs and
       replacements, dismantling, removal, transportation and delivery costs
       thereof, at rental charges consistent with those prevailing in the
       greater Boston area.

9.     Cost of premiums for all bonds and insurance, which the Contractor is
       required by the construction contract or this Lease, to purchase and
       maintain.

10.    Sales, use, or similar taxes related to the work and for which the
       Contractor is liable, which are imposed by any governmental authority.

11.    Permit fees, royalties, damage or infringement of patents and costs of
       defending suits therefor, and deposits lost for causes other than due to
       the Contractor's negligence.

12.    Losses and expenses, not compensated by insurance or otherwise, sustained
       by the Contractor in connection with the work, provided they have
       resulted from causes other than the fault or neglect of the Contractor.
       Such losses shall include settlements made with the written consent and
       reasonable approval by Landlord and Tenant. If, however, such loss
       requires reconstruction and the Contractor is placed in charge thereof,
       he shall be paid for his services a fee of ten percent (10%) of the cost
       of such work.

13.    Minor expenses such as telegrams, long distance telephone calls,
       telephone service at the site, expressage, drawing reproduction, mail
       service, special deliveries, and similar petty cash items incurred in
       connection with the Tenant's Work.

14.    Cost of all removal of debris and clean up.

15.    Costs incurred due to an emergency affecting the safety of persons and
       property.

16.    Other costs incurred in the performance of the work if and to the extent
       approved in advance in writing by the Tenant.

17.    The cost of temporary power and heat.


<PAGE>   118


                                   EXHIBIT "M"

                              INTENTIONALLY DELETED



<PAGE>   119

                                   EXHIBIT "N"

                              INTENTIONALLY DELETED


<PAGE>   120



                                 EXHIBIT "O(a)"

                           EXPANSION LOTS SIDE LETTER


                                                               November 17, 2000

RSA Security, Inc.
20 Crosby Drive
Bedford, Massachusetts 01730

       RE:  Building 3, Lot 1-3, 174 Middlesex Turnpike, Bedford Woods Office
            Park, Bedford, Massachusetts
            ------------------------------------------------------------------

Gentlemen:

       Reference is hereby made to that certain lease (the "Lease") dated as
November 15, 2000 and executed by and between the undersigned, Bedford Woods I
Limited Partnership (as "Landlord") and RSA Security, Inc. (as "Tenant").

       Whereas pursuant to the Lease the Landlord has provided the Tenant with
the certain Expansion Option for the construction of two (2) Expansion
Building(s), Building No. 1 of approximately 183,548 square feet to be located
on Lot 1-1 and Building No.2 of approximately 188,220 square feet to be located
on Lot 1-2 as such Lots are shown on that certain plan entitled "Plan of Land"
in Bedford, MA Prepared For The Gutierrez Company dated November 13, 2000",
scale 1" = 100' prepared by Hancock Survey Associates, Inc. (the "Plan") such
Lots 1-1 & 1-2 are hereinafter collectively referred to as "Expansion Lots" and
referred to individually as an "Expansion Lot" which Expansion Lots are located
in Bedford Woods Office Park, Bedford, Massachusetts (the "Park"), which lots
are currently owned by Landlord but will be conveyed to affiliates of the
Landlord;

       Whereas, Landlord would not agree to enter into the Lease without the
execution and delivery by Tenant of this Letter Agreement and Landlord is
relying thereon and entering into the Lease and;

       Whereas, the Tenant would not agree to enter into the Lease without the
execution and delivery to Tenant of this Letter Agreement and Tenant is relying
thereon and entering into the Lease;

       Now therefore, for good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, the undersigned hereby agree with
Landlord and Tenant as follows:


<PAGE>   121

       1. Any capitalized terms used herein and not specifically defined herein
shall have the meanings as set forth in the Lease.

       2. Tenant agrees that the Landlord shall have the right to convey said
Lot 1-1 and Lot 1-2 to Landlord's affiliates upon written notice to Tenant. Any
such Landlord's affiliates that take title to an Expansion Lot or Expansion Lots
shall be hereinafter referred to collectively as the "Expansion Lot Owners".
Tenant agrees that Tenant's Expansion Option shall at all times be subject to
the provisions of Exhibit "R" of the Lease. Provided Tenant has complied with
all of the terms and provision of the Lease and Exhibit R of the Lease including
but not limited to the requirement that there does not then exist any uncured,
continuing Event of Default under the Lease or under any Tenant Park Leases and
Tenant is then leasing, including subleasing, at least One-Hundred (100%)
Percent of the Building and One-Hundred (100%) Percent of all buildings under
the Tenant Park Leases and so long as the Expansion Option has not terminated in
accordance with the provisions of Exhibit R to the Lease, the Expansion Lot
Owners agree not to construct or permit the construction of any buildings on the
Expansion Lots and not to use the Expansion Lots for any purposes other than
providing for any required park drainage and utilities and for additional
parking and access to any buildings being leased to the Tenant in the Park.

       3. In the event the Expansion Lot Owners or their mortgagee(s) cannot or
do not construct the Expansion Building(s) on the Expansion Lots upon the
Tenant's election to exercise Tenant's Expansion Option in compliance with the
terms of this Letter Agreement and Exhibit R of the Lease, then the Expansion
Lots Owner(s) and their mortgagee(s) shall give Tenant written notice that it
cannot or will not construct the Expansion Building(s) on the Expansion Lots as
hereinabove set forth, and in such event Tenant shall have the option to
purchase the Expansion Lot(s) at the greater of Thirty Five Dollars ($35.00) per
developable building square foot on such Expansion Lots or the then fair market
value for such Expansion Lot(s)so purchased for a period of thirty (30) days
following receipt by Tenant of such mortgagee(s)' or Expansion Lot Owner(s)'
notice of its inability or decision not to construct the Expansion Buildings on
the Expansion Lots and the determination of fair market value as hereinafter
defined. The Expansion Lot Owner(s) shall cooperate with Tenant and promptly
provide Tenant with all applicable permits, licenses, plans, surveys, title
materials, testing information and other useful and relevant information, which
is not privileged, at no additional cost to Tenant but without representation or
warranty.

          The Fair Market Value ("Market Value") for the Expansion Lot(s) shall
be determined as follows:

          (a)    The Market Value shall be proposed by Expansion Lot Owner
                 within ten (10) days of receipt of Tenant's notice that it
                 intends to purchase the Expansion Lot(s) (the


                                       2
<PAGE>   122

                 "Expansion Lot Owner's Proposed Market Value") in
                 accordance with its right in the preceding paragraph. The
                 Expansion Lot Owner's Proposed Market Value shall be the
                 Market Value unless Tenant notifies Expansion Lots
                 Owner(s), within ten (10) days of Tenant's receipt of
                 Expansion Lot Owner(s)' Proposed Market Value, that
                 Expansion Lot Owner(s)' Proposed Market Value is not
                 satisfactory to Tenant ("Tenant's Rejection Notice").

          (b)    If the Market Value is not otherwise agreed upon by
                 Expansion Lot Owners and Tenant within ten (10) days after
                 Expansion Lots Owner(s)' receipt of Tenant's Rejection
                 Notice, then Tenant shall be deemed to have withdrawn its
                 exercise of the option unless Tenant shall have given
                 notice to Expansion Lot Owner(s), within five (5) days
                 after said ten (10) day period, that Tenant desires to
                 determine the Market Value by the following appraisal
                 procedure, which notice shall specify the name and address
                 of the appraiser designated by Tenant (the "Tenant's
                 Appraisal Notice"):

                     (i) Expansion Lot Owner(s) shall within five (5) days after
                     receipt of Tenant's Appraisal Notice, notify Tenant of the
                     name and address of the appraiser designated by Expansion
                     Lot Owners. Such two appraisers shall, within ten (10) days
                     after the designation of the second appraiser, make their
                     determinations of the Market Value in writing and give
                     notice thereof to each other and to Expansion Lot Owner and
                     Tenant. Such two (2) appraisers shall have ten (10) days
                     after the receipt of notice of each other's determination
                     to confer with each other and to attempt to reach agreement
                     as to the determination of the Market Value. If such
                     appraisers shall concur in such determination, they shall
                     give notice thereof to Expansion Lot Owner(s) and Tenant
                     and such concurrence shall be final and binding upon
                     Expansion Lot Owner(s) and Tenant. If such appraisers shall
                     fail to concur as to such determination within said ten
                     (10) day period, they shall give notice thereof to
                     Expansion Lot Owner(s) and Tenant and shall immediately
                     designate a third appraiser. If the two appraisers shall
                     fail to agree upon the designation of such third appraiser
                     within five (5) days after said ten (10) day period, then
                     they or either of them shall give notice of such failure to
                     agree to Expansion Lot Owner(s) and Tenant and if Expansion
                     Lot Owner(s) and Tenant fail to agree upon the selection of
                     such third appraiser within five (5) days after the
                     appraiser(s) appointed by the parties give notice

                                       3

<PAGE>   123

                     as aforesaid, then either party on behalf of both may apply
                     to the American Arbitration Association or any successor
                     thereto, or on his or her failure, refusal or inability to
                     act, to a court of competent jurisdiction, for the
                     designation of such third appraiser.

                     (ii) All appraisers shall be real estate appraisers or
                     consultants who shall have had at least seven (7) years
                     continuous experience in the business of appraising real
                     estate in the suburban Boston area.

                     (iii) The third appraiser shall conduct such hearings and
                     investigations as he or she may deem appropriate and shall,
                     within ten (10) days after the date of his or her
                     designation, make an independent determination of the
                     Market Value.

                     (iv) If none of the determinations of the appraisers varies
                     from the mean of the determinations of the other appraisers
                     by more than ten (10%) percent, the mean of the
                     determinations of the three (3) appraisers shall be the
                     Market Value for the Expansion Lot(s). If, on the other
                     hand, the determination of any single appraiser varies from
                     the mean of the determinations of the other two (2)
                     appraisers whose determinations are closest in number by
                     more than ten (10%) percent, the mean of the determination
                     of those 2 appraisers shall be the Market Value.

                     (v) The determination of the appraisers, as provided above,
                     shall be conclusive upon the parties and shall have the
                     same force and effect as a judgment made in a court of
                     competent jurisdiction.

                     (vi) Each party shall pay fees, costs and expenses of the
                     appraiser selected by it and its own counsel fees and
                     one-half (1/2) of all other expenses and fees of any such
                     appraisal.

        4. The Tenant acknowledges and agrees that the Expansion Lots Owners
shall have the right to further encumber the Expansion Lots by placing
mortgage(s) on the Expansion Lots of a total indebtedness of an amount not to
exceed Fifty (50%) percent of the value of the Expansion Lots, which value shall
be the value of the Expansion Lots determined by any proposed mortgagees'
appraiser. Further, the Tenant agrees to subordinate Tenant's Expansion Option,
the Notice of Lease and this Letter Agreement to such mortgage(s) provided such
mortgagee(s) agrees to either (a) recognize all Tenant's rights


                                       4

<PAGE>   124


contained in this Letter Agreement or (b) in the event such mortgagee(s) does
not agree to recognize all Tenant's rights contained in this Letter Agreement
then Tenant will still subordinate Tenant's Expansion Option, the Notice of
Lease and this Letter Agreement to such mortgage(s) if such mortgagee(s)
recognizes Tenant's right to purchase the Expansion Lots as set forth in
Paragraph 3 of this Letter Agreement.

         5. In the event that Tenant notifies the Expansion Lot Owner(s) of its
exercise of the Expansion Option as hereinabove set forth and as set forth in
the Lease and the Expansion Lot Owner(s) and Tenant fail to agree and execute a
mutually satisfactory Expansion Lease for the Expansion Building(s) within the
forty-five (45) day period following receipt of Tenant's notice of its election
to exercise the Expansion Option, the Expansion Lot Owner(s) and having used
reasonable efforts and acting in good faith to negotiate such Expansion Lease,
or if Tenant fails to comply with all of the terms, covenants and conditions of
Exhibit R to the Lease, then the Expansion Lot Owner(s) shall thereafter be free
to sell and/or lease or otherwise deal with the Expansion Lots to anyone. In
such event or if Tenant otherwise defaults in its obligations hereunder or under
Exhibit R to the Lease: (i) Tenant shall be deemed to have waived its rights
under this Letter Agreement and the Expansion Option in the Lease; (ii) the
undersigned shall have the unrestricted right to sell, lease or otherwise deal
with the Expansion Lots under whatever terms and conditions as negotiated by the
undersigned in their sole discretion; and (iii) Tenant's Expansion Option
hereunder shall terminate and be of no force and effect and with no further
obligations, rights or remedies of Landlord or Tenant relating to the Expansion
Option and this Letter Agreement or said exercise at law or in equity. The
recording by the Expansion Lot Owner(s) of an affidavit to such effect shall be
conclusive evidence of the termination or waiver of Tenant's Expansion Option.

         6. To the extent any one of the Expansion Lot Owner(s) fails to fulfill
its agreements hereunder, then Tenant agrees that such event shall not be
considered a Landlord default under the Lease and to look solely to such
Expansion Lot Owner(s) then equity interest in the Expansion Lots, as the case
may be, and all proceeds thereof and all insurance proceeds and condemnation
awards, subject to the prior claims of such Expansion Lot Owner(s)' mortgagee(s)
at the time owed for recovery of any judgment from such Expansion Lot Owner; it
being agreed and understood that neither such Expansion Lot Owner (original or
successor), nor any partner (general or limited), associate, participant,
principal (disclosed or undisclosed), agent, employee, trustee or other
fiduciary, beneficiary or, officer or any person or entity in or of any
partnership, association, joint venture, corporation or other entity, trust or
estate from time to time owning such Expansion Lot Owner(s)' interest in said
Expansion Lots, as the case may be, shall ever be personally liable for any such
judgment or for the payment of any monetary obligation to Tenant (it being
agreed

                                       5

<PAGE>   125


by Tenant that such exoneration from personal liability is and shall be absolute
and completely no exception whatsoever). Notice of the rights contained herein
shall be recorded by the Expansion Lot Owner(s)' at the appropriate Registry of
Deeds by notice in a form and substance reasonably satisfactory to Tenant and
Landlord.

         7. The Landlord and the Expansion Lot Owner(s) shall have the right to
convey the Expansion Lots to any affiliate of the Landlord or the Expansion Lot
Owner(s) including but not limited to (i) transfers and sales to Affiliates of
Landlord, Affiliates of Expansion Lot Owner(s) or Affiliates of The Gutierrez
Company, (ii) transfers or sales to any party of any limited partnership
interest in the limited partnership which transferee is Landlord or Expansion
Lot Owner(s), Expansion Lot Owners, or the affiliates of the General Partner,
family members or affiliates of the General Partner or of any limited partner,
or employees of the General Partner(s) or limited partners, (iii) transfers, or
sales of any general partnership interest in the limited partnership which is
Landlord to an Affiliate.

         As used herein an Affiliate shall mean as to any Landlord or Expansion
Lot Owners (i) Arturo J. Gutierrez, John A. Cataldo, or members of their
immediate family (as defined below and The Gutierrez Company or any of its
employees); (ii) the legal representative, successor or assignee of, or any
trustee of a trust for the benefit of Arturo J. Gutierrez, John A. Cataldo, or
members of their immediate family; or (iii) any entity of which a majority of
the voting interests is owned by any one or more of the persons referred to in
the preceding clauses (i) and (ii). Immediate family shall mean, with respect to
any person, his spouse, children, adopted children, parents, parents-in-law,
grandchildren and great-grandchildren.

         8. All references to the undersigned herein shall be deemed to refer to
that specific owner of each of the Expansion Lots, as the case may be for
purposes of giving or receiving notices, and pertaining to agreements or
recording affidavits sets forth hereunder. The undersigned agree that the
obligation of the undersigned hereunder may be enforced by either or both of the
Landlord or Tenant. This Letter Agreement shall be binding upon the successors
an assigns of Landlord and all future owners of said Expansion Lots and shall
inure to the benefit of Tenant and successors and assigns.


                                       6

<PAGE>   126


         Executed under seal this 17th day of November, 2000.


                                     Landlord:


                                     Bedford Woods Limited
                                     Partnership I
                                     By: The Gutierrez Company
                                         General Partner


                                      By:_________________________________
                                      Arturo J. Gutierrez, President

Acknowledged and Agreed to
on this 17th day of November, 2000

TENANT:  RSA Security, Inc.


By:_________________________
     Its:


                                       7

<PAGE>   127

                                 EXHIBIT "O(b)"

                       RIGHT OF FIRST REFUSAL SIDE LETTER




                                                               November 17, 2000

RSA Security, Inc.
20 Crosby Drive
Bedford, Massachusetts 01730

       RE:  Building 3, Lot 1-3, 174 Middlesex Turnpike, Bedford Woods Office
            Park, Bedford, Massachusetts
            ------------------------------------------------------------------

Gentlemen:

       Reference is hereby made to that certain lease (the "Lease") dated as
November 15, 2000 and executed by and between the undersigned, Bedford Woods
Limited Partnership I (as "Landlord") and RSA Security, Inc. (as "Tenant").

       Whereas pursuant to Exhibit "Q" of the Lease the Landlord has provided
the Tenant with the certain Right of First Refusal Option for the leasing of two
(2) Expansion Building(s), Building No. 1 of approximately 100 feet 183,548
square feet and Building No.2 of approximately 188,220 square feet or such other
configurations as Landlord or the owner of such Right of First Refusal Lots, as
hereinafter defined, shall present in a letter of intent from another
prospective tenant that the Landlord or the owner of such Right of First Refusal
Lots have accepted to be located on Lot 1-1 and leasing to be located on Lot 1-2
as such Lots are shown on that certain plan entitled "Plan of Land" in Bedford,
MA Prepared For The Gutierrez Company dated November 13, 2000", scale 1" = 100'
prepared by Hancock Survey Associates, Inc. (the "Plan") such Lots 1-1 & 1-2 are
hereinafter collectively referred to as "Right of First Refusal Lots" and
referred to individually as an "Right of First Refusal Lot" which Right of First
Refusal Lots are located in Bedford Woods Office Park, Bedford, Massachusetts
(the "Park"), which lots are currently owned by Landlord but will be conveyed to
affiliates of the Landlord;

       Whereas, Tenant and Landlord agree that this Right of First Refusal
Sideletter and the Right of First Refusal in Exhibit "Q" of the Lease are
subordinate to (i) the Expansion Lots Sideletter of even date herewith by and
between Landlord and Tenant and (ii) the Tenant's Expansion Option in Exhibit
"R" to the Lease and;

<PAGE>   128

       Whereas, Landlord would not agree to enter into the Lease without the
execution and delivery by Tenant of this Letter Agreement and Landlord is
relying thereon and entering into the Lease and;

       Whereas, the Tenant would not agree to enter into the Lease without the
execution and delivery to Tenant of this Letter Agreement and Tenant is relying
thereon and entering into the Lease;

       Now therefore, for good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, the undersigned hereby agree with
Landlord and Tenant as follows:

       1. Any capitalized terms used herein and not specifically defined herein
shall have the meanings as set forth in the Lease.

       2. Tenant agrees that the Landlord shall have the right to convey said
Lot 1-1 and Lot 1-2 to Landlord's affiliates upon written notice to Tenant. Any
such Landlord's affiliates that take title to a Right of First Refusal Lot or
Right of First Refusal Lots shall be hereinafter referred to collectively as the
"Right of First Refusal Lot Owners". Tenant agrees that Tenant's Right of First
Refusal Option shall at all times be subject to the provisions of Exhibit "Q" of
the Lease. Further Tenant acknowledges and agrees that (i) this Letter Agreement
and Right of First Refusal Option in Exhibit "Q" of the Lease shall be
subordinate to Tenant's Expansion Option in Exhibit "R" of the Lease and to the
Expansion Lots Sideletter of even date herewith and (ii) Tenant's rights under
this Letter Agreement and Right of First Refusal Option in Exhibit "Q" of the
Lease can only be exercised after Tenant's Right of First Refusal Option in
Exhibit "R" of the Lease has been terminated and the Expansion Lots Sideletter
has been terminated. Provided Tenant has complied with all of the terms and
provision of the Lease and Exhibit "Q" of the Lease including but not limited to
the requirement that there does not then exist any uncured, continuing Event of
Default under the Lease or under any Tenant Park Leases and Tenant is then
leasing, including subleasing, at least One-Hundred (100%) Percent of the
Building and One-Hundred (100%) Percent of all buildings under the Tenant Park
Leases and so long as the Right of First Refusal Option has not terminated in
accordance with the provisions of Exhibit "Q" to the Lease, the Right of First
Refusal Lot Owners agree not to construct or permit the construction of any
buildings on the Right of First Refusal Lots and not to use the Right of First
Refusal Lots for any purposes other than providing for any required park
drainage and utilities and for additional parking and access to any buildings
being leased to the Tenant in the Park.

       3. In the event the Right of First Refusal Lot Owners or their
mortgagee(s) cannot or do not construct the Right of First Refusal Building(s)
on the Right of First Refusal Lots upon the Tenant's election to exercise
Tenant's Right of First Refusal Option in compliance with the terms of this
Right of First Refusal Letter


                                       2

<PAGE>   129


Agreement and Exhibit "Q" of the Lease then the Right of First Refusal Lots
Owner(s) and their mortgagee(s)' shall give Tenant written notice that it cannot
or will not construct the Right of First Refusal Building(s) on the Right of
First Refusal Lots as hereinabove set forth, and in such event Tenant shall have
the option to purchase the Right of First Refusal Lots at the greater of Thirty
Five Dollars ($35.00) per developable building square foot on such Right of
First Refusal Lot(s) so purchased or the then fair market value for such Right
of First Refusal Lot(s) for a period of thirty (30) days following receipt by
Tenant of such mortgagee(s)' or Right of First Refusal Lot Owner(s)' notice of
its inability or decision not to construct the Expansion Buildings on the Right
of First Refusal Lots and the determination of fair market value as hereinafter
defined. The Right of First Refusal Lot Owner(s) shall cooperate with Tenant and
promptly provide Tenant with all applicable permits, licenses, plans, surveys,
title materials, testing information and other useful and relevant information,
which is not privileged, at no additional cost to Tenant but without
representation or warranty.

       The Fair Market Value ("Market Value") for the Right of First Refusal
Lot(s) shall be determined as follows:

       (a)    The Market Value shall be proposed by Right of First Refusal Lot
              Owner within ten (10) days of receipt of Tenant's notice that it
              intends to purchase the Right of First Refusal Lot(s) (the "Right
              of First Refusal Lot Owner's Proposed Market Value") in accordance
              with its right in the preceding paragraph. The Right of First
              Refusal Lot Owner's Proposed Market Value shall be the Market
              Value unless Tenant notifies Right of First Refusal Lots Owner(s),
              within ten (10) days of Tenant's receipt of Right of First Refusal
              Lot Owner(s)' Proposed Market Value, that Right of First Refusal
              Lot Owner(s)' Proposed Market Value is not satisfactory to Tenant
              ("Tenant's Rejection Notice").

       (b)    If the Market Value is not otherwise agreed upon by Right of First
              Refusal Lot Owners and Tenant within ten (10) days after Right of
              First Refusal Lots Owner(s)' receipt of Tenant's Rejection Notice,
              then Tenant shall be deemed to have withdrawn its exercise of the
              option unless Tenant shall have given notice to Right of First
              Refusal Lot Owner(s), within five (5) days after said ten (10) day
              period, that Tenant desires to determine the Market Value by the
              following appraisal procedure, which notice shall specify the name
              and address of the appraiser designated by Tenant (the "Tenant's
              Appraisal Notice"):

                     (i) Right of First Refusal Lot Owner(s) shall within five
                     (5) days after receipt of Tenant's

                                       3

<PAGE>   130


                     Appraisal Notice, notify Tenant of the name and address of
                     the appraiser designated by Right of First Refusal Lot
                     Owners. Such two appraisers shall, within ten (10) days
                     after the designation of the second appraiser, make their
                     determinations of the Market Value in writing and give
                     notice thereof to each other and to Right of First Refusal
                     Lot Owner and Tenant. Such two (2) appraisers shall have
                     ten (10) days after the receipt of notice of each other's
                     determination to confer with each other and to attempt to
                     reach agreement as to the determination of the Market
                     Value. If such appraisers shall concur in such
                     determination, they shall give notice thereof to Right of
                     First Refusal Lot Owner(s) and Tenant and such concurrence
                     shall be final and binding upon Right of First Refusal Lot
                     Owner(s) and Tenant. If such appraisers shall fail to
                     concur as to such determination within said ten (10) day
                     period, they shall give notice thereof to Right of First
                     Refusal Lot Owner(s) and Tenant and shall immediately
                     designate a third appraiser. If the two appraisers shall
                     fail to agree upon the designation of such third appraiser
                     within five (5) days after said ten (10) day period, then
                     they or either of them shall give notice of such failure to
                     agree to Right of First Refusal Lot Owner(s) and Tenant and
                     if Right of First Refusal Lot Owner(s) and Tenant fail to
                     agree upon the selection of such third appraiser within
                     five (5) days after the appraiser(s) appointed by the
                     parties give notice as aforesaid, then either party on
                     behalf of both may apply to the American Arbitration
                     Association or any successor thereto, or on his or her
                     failure, refusal or inability to act, to a court of
                     competent jurisdiction, for the designation of such third
                     appraiser.

                     (ii) All appraisers shall be real estate appraisers or
                     consultants who shall have had at least seven (7) years
                     continuous experience in the business of appraising real
                     estate in the suburban Boston area.

                     (iii) The third appraiser shall conduct such hearings and
                     investigations as he or she may deem appropriate and shall,
                     within ten (10) days after the date of his or her
                     designation, make an independent determination of the
                     Market Value.

                     (iv) If none of the determinations of the appraisers varies
                     from the mean of the determinations of the other appraisers
                     by more than


                                       4
<PAGE>   131


                     ten (10%) percent, the mean of the determinations of the
                     three (3) appraisers shall be the Market Value for the
                     Right of First Refusal Lot(s). If, on the other hand, the
                     determination of any single appraiser varies from the mean
                     of the determinations of the other two (2) appraisers whose
                     determinations are closest in number by more than ten (10%)
                     percent, the mean of the determination of those 2
                     appraisers shall be the Market Value.

                     (v) The determination of the appraisers, as provided above,
                     shall be conclusive upon the parties and shall have the
                     same force and effect as a judgment made in a court of
                     competent jurisdiction.

                     (vi) Each party shall pay fees, costs and expenses of the
                     appraiser selected by it and its own counsel fees and
                     one-half (1/2) of all other expenses and fees of any such
                     appraisal.

        4. The Tenant acknowledges and agrees that the Right of First Refusal
Lots Owners shall have the right to further encumber the Right of First Refusal
Lots by placing mortgage(s) on the Right of First Refusal Lots of a total
indebtedness of an amount not to exceed Fifty (50%) percent of the value of the
Right of First Refusal Lots, which value shall be the value of the Right of
First Refusal Lots determined by any proposed mortgagees' appraiser. Further,
the Tenant agrees to subordinate Tenant's Right of First Refusal Option, the
Notice of Lease and this Letter Agreement to such mortgage(s) provided such
mortgagee(s) agrees to either (a) recognize all Tenant's rights contained in
this Letter Agreement or (b) in the event such mortgagee(s) does not agree to
recognize all Tenant's rights contained in this Letter Agreement then Tenant
will still subordinate Tenant's Right of First Refusal Option, the Notice of
Lease and this Letter Agreement to such mortgage(s) if such mortgagee(s)
recognizes Tenant's right to purchase the Right of First Refusal Lots as set
forth in Paragraph 3 of this Letter Agreement.

         5. In the event that Tenant notifies the Right of First Refusal Lot
Owner(s) of its exercise of the Right of First Refusal Option as hereinabove set
forth and as set forth in the Lease and the Right of First Refusal Lot Owner(s)
and Tenant fail to agree and execute a mutually satisfactory Right of First
Refusal Lease for the Right of First Refusal Building(s) within the forty-five
(45) day period following receipt of Tenant's notice of its election to exercise
the Right of First Refusal Option, the Right of First Refusal Lot Owner(s)
having used reasonable efforts and acting in good faith to negotiate such Rights
of First Refusal Lease, or if Tenant fails to comply with all of the terms,
covenants and

                                       5

<PAGE>   132


conditions of Exhibit "Q" to the Lease, then the Right of First Refusal Lot
Owner(s) shall thereafter be free to sell and/or lease or otherwise deal with
the Right of First Refusal Lots to anyone. In such event or if Tenant otherwise
defaults in its obligations hereunder or under Exhibit "Q" to the Lease: (i)
Tenant shall be deemed to have waived its rights under this Letter Agreement and
the Right of First Refusal Option in the Lease; (ii) the undersigned shall have
the unrestricted right to sell, lease or otherwise deal with the Right of First
Refusal Lots under whatever terms and conditions as negotiated by the
undersigned in their sole discretion; and (iii) Tenant's Right of First Refusal
Option hereunder shall terminate and be of no force and effect and with no
further obligations, rights or remedies of Landlord or Tenant relating to the
Right of First Refusal Option and this Letter Agreement or said exercise at law
or in equity. The recording by the Right of First Refusal Lot Owner(s) of an
affidavit to such effect shall be conclusive evidence of the termination or
waiver of Tenant's Right of First Refusal Option.

         6. To the extent any one of the Right of First Refusal Lot Owner(s)
fails to fulfill its agreements hereunder, then Tenant agrees that such event
shall not be considered a Landlord default under the Lease and to look solely to
such Right of First Refusal Lot Owner(s) then equity interest in the Right of
First Refusal Lots, as the case may be, and all proceeds thereof and all
insurance proceeds and condemnation awards, subject to the prior claims of such
Right of First Refusal Lot Owner(s)' mortgagee(s) at the time owed for recovery
of any judgment from such Right of First Refusal Lot Owner; it being agreed and
understood that neither such Right of First Refusal Lot Owner (original or
successor), nor any partner (general or limited), associate, participant,
principal (disclosed or undisclosed), agent, employee, trustee or other
fiduciary, beneficiary or, officer or any person or entity in or of any
partnership, association, joint venture, corporation or other entity, trust or
estate from time to time owning such Right of First Refusal Lot Owner(s)'
interest in said Right of First Refusal Lots, as the case may be, shall ever be
personally liable for any such judgment or for the payment of any monetary
obligation to Tenant (it being agreed by Tenant that such exoneration from
personal liability is and shall be absolute and completely no exception
whatsoever). Notice of the rights contained herein shall be recorded by the
Right of First Refusal Lot Owner(s)' at the appropriate Registry of Deeds by
notice in a form and substance reasonably satisfactory to Tenant and Landlord.

         7. The Landlord and the Right of First Refusal Lot Owner(s) shall have
the right to convey the Right of First Refusal Lots to any affiliate of the
Landlord or the Right of First Refusal Lot Owner(s) including but not limited to
(i) transfers and sales to Affiliates of Landlord, Affiliates of Right of First
Refusal Lot Owner(s) or Affiliates of The Gutierrez Company, (ii) transfers or
sales to any


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<PAGE>   133


party of any limited partnership interest in the limited partnership which
transferee is Landlord, Right of First Refusal Lot Owners, or the affiliates of
the General Partner, family members or affiliates of the General Partner or of
any limited partner, or employees of the General Partner(s) or limited partners,
(iii) transfers, or sales of any general partnership interest in the limited
partnership which is Landlord or Right of First Refusal Lot Owner(s) to an
Affiliate.

         As used herein an Affiliate shall mean as to any Landlord or Right of
First Refusal Lot Owners (i) Arturo J. Gutierrez, John A. Cataldo, or members of
their immediate family (as defined below and The Gutierrez Company or any of its
employees); (ii) the legal representative, successor or assignee of, or any
trustee of a trust for the benefit of Arturo J. Gutierrez, John A. Cataldo, or
members of their immediate family; or (iii) any entity of which a majority of
the voting interests is owned by any one or more of the persons referred to in
the preceding clauses (i) and (ii). Immediate family shall mean, with respect to
any person, his spouse, children, adopted children, parents, parents-in-law,
grandchildren and great-grandchildren.

         8. All references to the undersigned herein shall be deemed to refer to
that specific owner of each of the Right of First Refusal Lots, as the case may
be for purposes of giving or receiving notices, and pertaining to agreements or
recording affidavits sets forth hereunder. The undersigned agree that the
obligation of the undersigned hereunder may be enforced by either or both of the
Landlord or Tenant. This Letter Agreement shall be binding upon the successors
an assigns of Landlord and all future owners of said Right of First Refusal Lots
and shall inure to the benefit of Tenant and successors and assigns.

         Executed under seal this 17th day of November, 2000.


                                        Landlord:


                                        Bedford Woods Limited Partnership I
                                        By: The Gutierrez Company
                                            General Partner


                                         By:______________________________
                                         Arturo J. Gutierrez, President



                                       7

<PAGE>   134


Acknowledged and Agreed to
on this 17th day of November, 2000

TENANT:  RSA Security, Inc.


By:_____________________________
     Its:



                                       8

<PAGE>   135

                                   EXHIBIT "P"

                                   MARKET RENT


       The market rent for the Premises shall be the then fair market rent for
comparable leases completed in comparable office space located along and near
Route 3 and the Middlesex Turnpike between Route 128 and Route 495 in the Towns
of Bedford, Burlington, Billerica and Chelmsford, Massachusetts, taking into
account, but not limited to, rental rate, brokerage fees, lease term, base year,
tenant improvements, and leasing concessions offered to tenants in the
marketplace, which such rent (the "Market Rent") shall be determined as follows:

(a)    The Market Rent shall be proposed by Landlord within fifteen (15) days of
       receipt of Tenant's notice that it intends to exercise its option to
       extend the Term as specified in Exhibit F of this Lease hereof (the
       "Landlord's Proposed Market Rent"). The Landlord's Proposed Market Rent
       shall be the Market Rent unless Tenant notifies Landlord, within fifteen
       (15) days of Tenant's receipt of Landlord's Proposed Market Rent, that
       Landlord's Proposed Market Rent is not satisfactory to Tenant ("Tenant's
       Rejection Notice").

(b)    If Tenant delivers Tenant's Rejection Notice and the Market Rent is not
       otherwise agreed upon by Landlord and Tenant within forty-five (45) days
       after Landlord's receipt of Tenant's notice that it intends to exercise
       its option to extend the Term, then the Market Rent shall be determined
       by the following appraisal procedure:

       1.     Within five (5) days of the expiration of said forty-five (45) day
              period, Tenant shall give notice to Landlord, which notice shall
              specify the name and address of the commercial real estate broker
              designated by Tenant (the "Tenant's Appraisal Notice"). All such
              real estate brokers shall have at least ten (10) years experience
              in the Boston Real Estate Market. The last five (5) years of which
              is in the Suburban Boston office/R&D market. Landlord shall within
              five (5) days after receipt of Tenant's Appraisal Notice, notify
              Tenant of the name and address of the real estate broker
              designated by Landlord. Such two real estate brokers shall, within
              twenty (20) days after the designation of the second real estate
              broker, make their determinations of the Market Rent in writing
              and give notice thereof to each other and to Landlord and Tenant.
              Such two (2) real estate brokers shall have twenty (20) days after
              the receipt of notice of each other's determination to confer with
              each other and to attempt to reach agreement as to the
              determination of the Market Rent. If such real estate brokers
              shall concur in such determination, they shall give notice thereof
              to Landlord and Tenant and such concurrence shall be final and
              binding upon Landlord and Tenant. If such real estate brokers
              shall fail to concur as to such determination within said twenty
              (20) day period, they shall give notice thereof to Landlord and
              Tenant and shall immediately designate a third real estate broker.
              If the two real estate brokers shall fail to agree upon the
              designation of such third real estate broker within five (5) days
              after said twenty (20) day period, then they or either of them
              shall give notice of such failure to agree to Landlord and Tenant
              and if Landlord and Tenant fail to agree upon the selection of
              such third real estate broker within five (5) days after the real
              estate broker(s) appointed by the parties give notice as
              aforesaid, then either party on behalf of both may apply to the
              American Arbitration Association or any

<PAGE>   136

              successor thereto, or on his or her failure, refusal or inability
              to act, to a court of competent jurisdiction, for the designation
              of such third real estate broker.

       2.     All real estate brokers shall be independent real estate real
              estate brokers or consultants who shall have had at least fifteen
              (15) years continuous experience in the business of appraising
              real estate in said market.

       3.     The third real estate broker shall conduct such investigations as
              he or she may deem appropriate and shall, within ten (10) days
              after the date of his or her designation, make an independent
              determination of the Market Rent.

       4.     If none of the determinations of the real estate brokers varies
              from the mean of the determinations of the other real estate
              brokers by more than ten (10%) percent, the mean of the
              determinations of the three (3) real estate brokers shall be the
              Market Rent for the Premises. If, on the other hand, the
              determination of any single real estate broker varies from the
              mean of the determinations of the other two (2) real estate
              brokers by more than ten (10%) percent, the mean of the
              determination of the two (2) real estate brokers whose
              determinations are closest shall be the Market Rent.

       5.     The determination of the real estate brokers, as provided above,
              shall be conclusive upon the parties and shall have the same force
              and effect as a judgment made in a court of competent
              jurisdiction.

       6.     Each party shall pay fees, costs and expenses of the real estate
              broker selected by it, its own counsel fees, and one-half (1/2) of
              all other expenses and fees of any such appraisal.


                                       2
<PAGE>   137


                                   EXHIBIT "Q"

                             RIGHT OF FIRST REFUSAL

         Landlord (including Landlord's affiliates, successors and assigns and
all other successors in title, except as provided in Paragraph III hereof)
agrees it shall, so long as there does not then exist any uncured, continuing
Event of Default under this Lease or in any lease of Tenant in the Park (the
"Tenant Park Leases"), and this Lease is then in existence and in full force and
effect, so long as Tenant is then leasing, including subleasing, at least one
hundred percent (100%) of the Building and one hundred percent (100%) of all
buildings under the Tenant Park Leases, and so long as such Right of First
Refusal has not been terminated in accordance with this Exhibit "Q", at the time
such Right of First Refusal is exercisable, grant the right to lease either or
both of the proposed Building No. 2 and Building No. 1 (the size and footprint
of the Expansion Building(s) shall be as specified in the Triggering Proposal
generally as shown on a site plan prepared by Symmes, Maini & McKee Associates,
Inc. titled "The Gutierrez Company, Bedford Woods, Bedford, MA, dated February
4, 1999, as revised through November 8, 2000 and November 10, 2000, Drawings
C1.1, C2.1, C2.2, C3.1, C3.2, C4.1, C4.2, C5.1, C5.2, C6.1, C6.2, C6.3 and
C6.4, attached as Exhibit "A" to this Lease (the "Expanded Buildings Site
Plan"), or such other size and footprint as is agreed upon by Landlord and such
other prospective tenant), (the "Expansion Building(s)") on the same terms and
conditions as those set forth in a proposal from Landlord to another prospective
tenant, which has been accepted by that prospective tenant, or on the basis of a
letter of intent from another prospective tenant, which has been accepted by
Landlord for either or both of such Building(s) (the "Triggering Proposal").
Such right is to be exercised by written notice from Tenant to Landlord
accompanied by a Five Hundred Thousand Dollar ($500,000.00) Deposit within ten
(10) business days of Landlord providing Tenant with notice of such prior offer
to lease such Expansion Building(s) or portion thereof accompanied by a copy of
the accepted proposal or letter of intent for such Expansion Building(s). In the
event that the Expansion Building(s) which is the object of the accepted
proposal or letter of intent is Building No. 1 and Tenant has not previously
exercised its option or right of refusal for Building No. 2, then Tenant's
exercise of this right of first refusal shall be for Building No. 2 rather than
Building No. 1.

         Notwithstanding anything to the contrary in this Exhibit "Q", if Tenant
fails to notify Landlord of its exercise of this right within the time period
set forth above and with the Deposit specified above and/or execute and deliver
the Lease for such space in accordance with this Exhibit "Q" (i) Landlord shall
have the unrestricted right to lease such Expansion Building(s) that were the
subject of the Triggering Proposal upon whatever terms and conditions as are
negotiated by Landlord; (ii) Tenant shall be deemed to have waived all its
rights to such Expansion Building(s) under this Exhibit "Q"; and (iii) Tenant's
Right of First Refusal hereunder shall terminate as to such Expansion
Building(s).

         If Tenant exercises this Right of First Refusal and then fails to
execute the Lease for such Expansion Building(s) as required herein, then all
Tenant's Rights of First Refusal in Exhibit Q under this Lease and Expansion
Rights in Exhibit R of this Lease shall terminate.

I.       EXPANSION BUILDINGS

<PAGE>   138

         The Lease for the Expansion Building(s) shall be in the same form and
substance as this Lease, and, except as otherwise set forth in the Triggering
Proposal, on the same terms and conditions as are set forth in this Lease.
Unless otherwise specified in the Triggering Proposal, the Lease for the
Expansion Building(s) shall provide for a Scheduled Expansion Building Term
Commencement Date, the former to be mutually agreed upon by Landlord and Tenant
in good faith, but in no event less than ten (10) months or more than thirteen
(13) months after obtaining all required permits and approvals for construction
of the Expansion Building(s), considering such factors as weather and material
availability (it being agreed by Landlord and Tenant that such Right of First
Refusal Notice by Tenant occurring between October 1 and March 1 may, at
Landlord's option, add two (2) additional months to the Expansion Scheduled Term
Commencement Date for such space beyond that which would otherwise be expected.
If Tenant exercises the Right of First Refusal for both Buildings No. 2 and No.
1 at the same time, then the second building, either Building No. 2 or No. 1 at
Tenant's election may be delivered by Landlord up to four (4) months after the
first building to be delivered, and only the first building to be delivered
shall conform to the delivery schedule previously set forth in the paragraph.
The Lease for the Expansion Building(s) shall also provide (i) for an Expansion
Outside Delivery Date of one hundred forty (140) days after the Expansion
Scheduled Term Commencement Date, (ii) Tenant the right to cancel the Lease for
the Expansion Building(s) in the event that the Expansion Building(s) are not
delivered on or before the Expansion Outside Delivery Date, as extended for
delays due to Force Majeure, up to an aggregate of forty-five (45) days, or
Tenant's Delay as therein described. The proposed Lease for the Expansion
Building(s) shall be delivered by Landlord to Tenant promptly after such
Expansion Notice to Tenant, and a mutually agreed upon Lease shall be executed
by Landlord and Tenant within forty-five (45) days from the date of Tenant's
receipt of a proposed form of Lease for the Expansion Building(s) from Landlord
in the form as herein required, unless such date is extended by mutual agreement
of both parties hereto. Tenant and Landlord shall use reasonable efforts, each
acting in good faith, to execute the Lease for the Expansion Building(s) within
said forty-five (45) days from the date of Tenant's receipt of a proposed form
from Landlord. In the event that both parties execute said Expansion Building
Lease within such forty-five (45) day period, then Landlord shall promptly
return the Five Hundred Thousand Dollar ($500,000.00) Deposit to Tenant. If said
lease is not executed by both parties within such forty-five (45) day period,
Landlord having used reasonable efforts and acting in good faith, then Landlord
shall retain the Five Hundred Thousand Dollar ($500,000.00) Deposit as
liquidated damages.


II.      ADDITIONAL EXPANSION PROVISIONS

         Unless otherwise provided in the Triggering Proposal, the building
quality, plans and specifications for the Expansion Building(s) shall be in
accordance with the Expanded Buildings Site Plan and Building Specifications
substantially comparable to the Building initially leased herein with no
Landlord Allowance towards Tenant's Work, except as hereinafter provided, which
such plans and specifications shall be set forth in the Lease for the Expansion
Building(s). Without limiting the foregoing, the building quality, fit and
finish of the Expansion Buildings shall be substantially comparable to the
Buildings initially leased herein based on Landlord's Plans and specifications
for the initial Building.

         Landlord's obligation to construct the Expansion Building(s) is
contingent upon: (i) Tenant's net worth as set forth in Tenant's most recent 10Q
Report prior to such Expansion Exercise Date or if


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<PAGE>   139


such report is unavailable, most current audited financial report, being not
less than Two Hundred Fifty Million Dollars ($250,000,000.00), (ii) Landlord's
ability, using good faith effort to finance the non-land project cost of such
building(s), or such portion thereof as the Landlord elect to finance; and (iii)
upon Landlord's ability, using a good faith diligent effort to obtain applicable
permits and approvals required under building, zoning and environmental laws,
codes, rules and regulations and other laws then affecting the use and
development of such land in order to construct the Expansion Building(s) in
accordance with all of the terms of this Lease. In such event Landlord shall
notify Tenant of such inability to finance the non-land project cost of such
Expansion Building(s) and Tenant shall have the option, to be exercised within
thirty (30) days of Landlord's notice of such inability to finance the non-land
project cost of such Expansion Building(s), to commit in writing to provide
Landlord with such first mortgage financing, both construction and long term
permanent financing of at least fifteen (15) year maturity with a twenty (20)
year loan amortization schedule. The interest to be charged in the construction
loan shall be at the rate of LIBOR (30 to 90 day as may be selected from time to
time by Landlord) plus 185 Basis Points. It shall carry a construction
completion guarantee from The Gutierrez Company and be guaranteed by The
Gutierrez Company, such guarantees to be null and void and of no further force
and effect in the event of Tenant's Bankruptcy or Tenant's assignment for the
benefit of creditors. The long term permanent loan shall be for a fifteen (15)
year term, with a twenty (20) year amortization schedule, at a rate equal to the
ten (10) year U.S. Treasury Bond Rate on the date of such Tenant Financing
Commitment plus 185 Basis Points. It shall be non-recourse (except the standard
fraud, misrepresentation, and hazard waste carve outs). Both loans shall be
supported by the standard documents and provisions for such loans mutually
acceptable to Landlord and Tenant. At Landlord's option the form of the loan
documentation will be the same as a recent loan to Landlord or its affiliates by
institutional construction and long term permanent lenders for a loan of similar
principal amount within the previous three (3) year period, or if Landlord has
not obtained such financing within such three (3) year period, the most recent
institutional loan to Landlord of a similar principal amount; The Tenant's
interest in such loans shall also secure Tenant's Lease obligations by Tenant
executing and delivering to Landlord a pledge and first security interest in
Tenant's interest in said loans to Landlord, with the Landlord, in the event of
Tenant's bankruptcy or assignment for the benefit of creditors, having the right
to offset Landlord's first mortgage loan obligation to Tenant against Tenant's
Lease obligations to Landlord.

         Further, notwithstanding any language to the contrary contained in this
Exhibit "Q", in the event that Tenant's Right of First Refusal as to the
Expansion Building(s) expires or has otherwise been terminated pursuant to the
above provisions of this Exhibit "Q", then Landlord shall have, at any time
thereafter during the Term of this Lease, the right to construct the Expansion
Building(s) (or a portion thereof), adjacent to the Building or elsewhere on the
Lot, and lease such space to any third party upon such terms and conditions as
are negotiated by Landlord in its sole and absolute discretion, and Tenant shall
have no further rights thereto. Landlord and Tenant hereby further acknowledge
and agree that in such event, the Expansion Building(s) may be enlarged or
reduced by Landlord in accordance with applicable laws, codes, rules and
regulations.

         III. Notwithstanding Landlord's obligations as set forth in this
Exhibit "Q", in the event that Landlord's mortgage lender institutes foreclosure
proceedings and/or becomes mortgagee in possession of the Building, then
Landlord's Right of First Refusal obligations hereunder shall be of no force and
effect, and Landlord's failure to comply with such obligations shall not
constitute a default by Landlord under the Lease until such time, if ever, as
such foreclosure proceedings and/or Landlord's lender's


                                       3
<PAGE>   140

mortgagee in possession status shall terminate and the immediate pre-foreclosure
or pre-mortgagee in possession Landlord again controls the Building. Further,
should Landlord's lender or anyone acquiring title to the property through it,
either by deed in lieu of foreclosure, foreclosure or otherwise, become
Landlord, then such Right of First Refusal option shall terminate.


                                       4


<PAGE>   141

                                   EXHIBIT "R"

                                EXPANSION OPTION

         Landlord (including Landlord's affiliates, successors and assigns and
all other successors in title, except as provided in Paragraphs III or IV
hereof) agrees it shall hold available for Tenant, subject to the conditions of
this Exhibit "R", Lots 1 and 2, as described in Exhibit "_" of this Lease (the
"Expansion Land") for the construction of two four-story buildings, so-called
Building No. 2 of 188,220+/- square feet and Building No. 1 of 183,548+/- square
feet (the "Expansion Building(s)"). The size and footprint of the Expansion
Building(s) shall be generally as shown on a site plan prepared by Symmes, Maini
& McKee Associates, Inc., titled "The Gutierrez Company, Bedford Woods, Bedford,
MA, dated February 4, 1999, as revised through November 8, 2000 and November 10,
2000, Drawings C1.1, C2.1, C2.2, C3.1, C3.2, C4.1, C4.2, C5.1, C5.2, C6.1, C6.2,
C6.3 and C6.4 attached as Exhibit "A" to this Lease (the "Expanded Buildings
Site Plan"), or such other size and footprint as is reasonably agreed upon by
Landlord and Tenant. Landlord acknowledges and agrees not to construct or permit
the construction of any buildings in, on or under the Expansion Land and not to
use the Expansion Land for purposes other than for providing the required park
drainage and utilities, and for parking and access to Tenant's Premises pursuant
to the provisions of any of the leases to Tenant in the Park (the "Tenant Park
Leases"), and subject to the conditions of this Exhibit "R". So long as there
does not then exist any uncured, continuing Event of Default under this Lease or
under any of the Tenant Park Leases, and this Lease is then in existence and in
full force and effect, so long as Tenant is then leasing, including subleasing,
at least one hundred percent (100%) of the Building and one hundred percent
(100%) of all buildings under the Tenant Park Leases, and so long as such
expansion option has not been terminated in accordance with this Exhibit "R",
Landlord shall be required to hold the Expansion Land available as aforesaid, or
to cause an affiliate, successor or assign of Landlord, or any other successor
in title, to hold the Expansion Land available as aforesaid, necessary for said
Expansion Building(s), until the earlier to occur of (i) the option for the
Expansion Building(s) has been terminated in accordance with this Exhibit "R" or
(ii) until such date which is the later of (a) January 3, 2003, or (b) 60 days
after notice from Landlord that the 300,000 square foot limitation imposed by
MEPA on Research and Development space which can be constructed in the Park
("MEPA Limitation") has been lifted, either without limitation or sufficient to
allow the construction of Building No. 2. Any exercise by Tenant of its
expansion option hereunder for a single building shall be first exercised for
Building No. 2. If the MEPA limitation is lifted in its entirety, then Tenant
may exercise its option for both Building No. 2 and Building No. 1. If Tenant
elects to exercise its expansion option for only Building No. 2, then the
expansion option for Building No. 1 will be extended until the later of sixty
(60) days after completion of Building No. 2 or until sixty (60) days after
Landlord's notice that the MEPA Limitation has been lifted sufficient to allow
the construction of Building No. 1.

         Tenant acknowledges and agrees that in the event Tenant fails to
exercise its Expansion Option as set forth in this Exhibit "R" on or before the
later to occur of January 3, 2003, or sixty (60) days after notice from Landlord
that the MEPA Limitation has been lifted, then the Tenant's Expansion Option as
set forth herein shall be terminated and shall be null and void and have no
further force and effect; thereafter Landlord or its affiliates shall not longer
be required to hold the Expansion Land for the Expansion Buildings(s) for Tenant
as contemplated hereunder.

         Landlord has obtained the following permits for the construction of the
Expansion Building(s): Indirect Access Permit from the Massachusetts Highway
Department, Order of Conditions, Site Plan

<PAGE>   142


Approval, Variance for Four Story Height of the Expansion Buildings, Special
Permit from the Planning board for parking spaces in Excess of 2.5 per 1,000
square feet of building area, Earth Removal Permit, Storm Water Discharge
Permit, and Street Opening Approval. In addition to the MEPA Limitation set
forth above, the Landlord acknowledges and agrees that upon the timely written
exercise of the Tenant's election of its expansion option for Building No. 1 or
Building No. 2, Landlord shall exercise good faith efforts to obtain all other
approvals and permits necessary for the construction of the Expansion
Building(s) including, but not limited to all zoning, subdivision, building
permits, sewer connection permits, wetland, environmental permits and approvals
necessary for the construction of the Expansion Building(s) generally similar to
the footprint and site plan shown on the Expanded Buildings Site Plan. In
addition to said additional approvals and permits set forth in the immediately
preceding sentence, in the event that any of the existing permits currently held
by Landlord referenced above expire prior to the Tenant's written exercise of
its Expansion Option in accordance with the provisions of this Exhibit "R", or
in the event that any applicable governmental authorities require modification
to the Expanded Buildings Site Plan or to any of the existing permits or
approvals, then Landlord and Tenant hereby further agree that they will work and
cooperate with each other in order to modify the provisions of this Exhibit "R"
to accommodate such altered or additional permits for the Expansion Building(s).

         If, after having exercised good faith efforts, Landlord is unable to
obtain all such necessary permits and approvals for the construction of the
Expansion Building(s) by the Expansion Permit Date, as described in Paragraph I
below, as it may be extended, then this Exhibit "R", including Paragraph I
hereof shall be null and void and of no further force and effect, and Landlord
or its affiliates shall no longer be required to hold the Expansion Land
required for the Expansion Building(s) contemplated hereunder.

III.     EXPANSION BUILDING(S)

         In the event that Tenant desires to exercise its option to lease and
occupy the Expansion Building(s), and there does not then exist any uncured,
continuing Event of Default hereunder, and Tenant is leasing at least one
hundred percent (100%) of the Building and all buildings under the Tenant Park
Leases, written notice of Tenant's intention to lease and occupy such Expansion
Building(s) (the "Expansion Notice") must be given to Landlord not later than
such date which is sixty (60) days after the earlier of January 3, 2003, or
after notice from Landlord of the lifting of the MEPA Limitation as specified
above (the "Expansion Exercise Date"). If Tenant elects to expand by leasing the
Expansion Building(s) (the "Lease for the Expansion Building(s)") as herein
provided, the annual Fixed Rent for the Expansion Building(s) shall be an amount
equal to the Market Rent for such space determined in accordance with Exhibit
"P" of this Lease on the Expansion Exercise date, but in no event less than the
then rent payable under the last building leased by Tenant in the Park, such
rent not having been reduced by any Tenant's Contribution to Landlord's Work or
similar term for reimbursement for Landlord's Work under such Tenant Park Lease
as provided in Section 3.5 of this Lease. The Fixed Rent for such Expansion
Building(s) shall also be adjusted by crediting Tenant's Annual Fixed Rent with
the value, if any, of the "Difference" between the agreed upon $2.50/SF of
Expansion Building(s) Tenant's cooperating broker's commission and the broker's
commission on expansion space customarily paid to a tenant's cooperating broker
in the West Suburban Massachusetts office/R&D Market at the time of such
expansion exercise by Tenant. Such Difference, if any, to be calculated by
multiplying the Difference on a SF basis by the constant derived by amortizing
the ten (10) year U.S. Treasury Bond Rate on the Exercise Date plus 185 basis
points over the term of subject expansion lease. Tenant shall notify


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<PAGE>   143


Landlord of its determination of such Difference, if any, on the Expansion
Exercise Date. If Landlord and Tenant are unable to agree upon such Difference,
if any, then the Difference shall be determined by arbitration by brokers as set
forth in Exhibit "P" hereof.

         Tenant is granted the option to contribute up to Fifteen Dollars per
square foot ($15.00/SF) toward the cost of Landlord's Work on any such Expansion
Building. Such election is to be made simultaneously with Tenant's Expansion
election. Should Tenant make such election to contribute to the cost of Landlord
Work, then the Fixed Rent payable in each year of the Initial Term of the Leases
for the Expansion Building(s) shall be reduced by an amount equal to the amount
so contributed times the constant resulting from amortizing the then current
ten-year treasury bond yield plus one hundred eighty-five (185) basis points
over twenty (20) years. But for such rent reduction, the Fixed Rent payable
hereunder during the Initial Term will be as set forth previously in this
Exhibit "R". Any such Tenant contribution toward the cost of Landlord's Work
will be paid to Landlord within fifteen (15) days of Substantial Completion of
the Expansion Building(s). In order to guarantee Tenant's obligation to make
such Contribution toward the cost of Landlord's Work, Tenant shall provide an
irrevocable letter of credit satisfactory to Landlord's construction mortgagee
in the amount so selected. After such election, failure to make such
Contribution, or provide such irrevocable letter of credit, as specified herein
shall be an event of default under this Lease and under the Lease for the
Expansion Building(s).

         The Lease for the Expansion Building(s) shall be in the same form and
substance as this Lease, and, except as herein set forth, on the same terms and
conditions as are set forth in this Lease and shall be for a Term of fifteen
(15) years. Landlord agrees to in good faith consider any proposal by Tenant to
include Tenant Improvements in any Leases for the Expansion Building with the
Fixed Rent for such Expansion Buildings to be increased to reflect such Tenant
Improvements. The Landlord may decide in its sole and absolute discretion
whether or not to include Tenant Improvements in any Expansion Building(s). The
Lease for the Expansion Building(s) shall provide for an Expansion Term
Commencement Date to be mutually agreed upon by Landlord and Tenant in good
faith, but in no event less than ten (10) months or more than thirteen (13)
months after obtaining all required permits and approvals for construction of
the Expansion Building(s), considering such factors as weather and material
availability (it being agreed by Landlord and Tenant that such Expansion Notice
by Tenant occurring between October 1 and March 1 may, at Landlord's option, add
two (2) additional months to the Expansion Scheduled Term Commencement Date for
such space beyond that which would otherwise be expected. If Tenant elects
expansion for both Buildings No. 2 and No. 1 at the same time, then the second
building, either Building No. 2 or No. 1 at Tenant's election may be delivered
by Landlord up to four (4) months after the first building to be delivered, and
only the first building to be delivered shall conform to the delivery schedule
previously set forth in the paragraph. The Lease for the Expansion Buildings
shall also provide (i) for an Expansion Outside Delivery Date of one hundred
forty (140) days after the Expansion Scheduled Term Commencement Date, (ii)
Tenant shall have the right to cancel the Lease for the Expansion Building(s) in
the event that the Expansion Building(s) are not delivered on or before the
Expansion Outside Delivery Dates, as extended for delays due to Force Majeure,
up to an aggregate of forty-five (45) days, or due to Tenant's Delay as therein
described. The proposed form of Lease for the Expansion Building(s) shall be
delivered by Landlord to Tenant promptly after such Expansion Notice to Tenant,
and a mutually agreed upon Lease shall be executed by Landlord and Tenant within
forty-five (45) days from the date of Tenant's receipt of a proposed Lease for
the Expansion Building(s) from Landlord in the form as herein required, unless
such date is extended by mutual agreement of both parties hereto. Tenant and
Landlord shall use reasonable efforts, each acting


                                       3
<PAGE>   144

in good faith, to execute the Lease for the Expansion Building(s) within said
forty-five (45) days from the date of Tenant's receipt of a proposed form from
Landlord.

         If not already obtained in connection with the construction of the
original Building, Landlord agrees to exercise good faith efforts to obtain or
extend all necessary permits and approvals to construct the Expansion
Building(s) within twelve (12) months after receipt of the Expansion Notice (the
"Expansion Permit Date"). If Tenant fails to exercise its option as to the
Expansion Building(s) or exercises its option in a timely manner but thereafter
fails to execute and deliver the Lease for the Expansion Building(s) on or prior
to the time period as hereinabove set forth in accordance with the provision of
this Exhibit "R", or, if after proceeding diligently and using good faith
efforts to obtain all required permits and approvals to construct such space by
the Expansion Permit Date, Landlord is unable to obtain all of such permits and
approvals, then, subject to the terms and provisions contained in this Exhibit
"R", Tenant's option as to the Expansion Building(s) and the rights and
obligations of both Landlord and Tenant under this Paragraph I shall be extended
until sixty (60) days after the earlier of (i) the Date on which Landlord is
able to obtain all of such required permits and approvals required to construct
such Expansion Building(s) or (ii) the Date which is forty-eight (48) months
after receipt of the Expansion Notice by Landlord, terminate forthwith and be of
no further force and effect.

IV.      ADDITIONAL EXPANSION PROVISIONS

         The building quality, plans and specifications for the Expansion
Building(s) shall be in accordance with the Expanded Buildings Site Plan and
Building Specifications substantially comparable to the Building initially
leased herein with no Landlord Allowance for Tenant's Work, except as
hereinafter provided, which such plans and specifications shall be set forth in
the Lease for the Expansion Building(s). Without limiting the foregoing, the
building quality, fit and finish of the Expansion Buildings shall be
substantially comparable to the Buildings initially leased herein based on
Landlord's Plans and specifications for the initial Building.

         V. Landlord's obligation to construct the Expansion Building(s) is
contingent upon: (i) Tenant's Net Worth as set forth in the most recent 10Q
Report of Tenant prior to the Expansion Exercise Date or if such report
unavailable, the most current audited financial report, being not less than Two
Hundred Fifty Million Dollars ($250,000,000.00), (ii) Landlord's ability using
good faith efforts to finance the non-land project cost of such Expansion
Building(s), or such lesser portion thereof as the Landlord elects to finance,
at the annual Fixed Rent as determined in Paragraph I and above; In such event
Landlord shall notify Tenant of such inability to finance the non-land project
cost of such Expansion Building(s) and Tenant shall have the option, to be
exercised within thirty (30) days of landlord's notice of such inability to
finance the non-land project cost of such Expansion Building(s), to commit in
writing to provide Landlord with such first mortgage financing, both
construction and long term permanent financing of at least fifteen (15) year
maturity with a twenty (20) year loan amortization schedule. The interest to be
charged in the construction loan shall be at the rate of LIBOR (30 to 90 day as
may be selected from time to time by Landlord) plus 185 Basis Points. It shall
carry a completion guarantee from The Gutierrez Company and be guaranteed by The
Gutierrez Company, such guarantees to be null and void and of no further force
and effect in the event of Tenant's Bankruptcy or assignment for the benefit of
creditors. The long term permanent loan shall be for a fifteen (15) year term,
with a twenty (20) year amortization schedule, at a rate equal to the ten (10)
year U.S. Treasury Bond Rate on

                                       4

<PAGE>   145

the date of such Tenant Financing Commitment plus 185 Basis Points. It shall be
non-recourse (except the standard fraud, misrepresentation, and hazard waste
carve outs). Both loans shall be supported by the standard documents and
provisions for such loans mutually acceptable to Landlord and Tenant. At
Landlord's option the form of the loan documentation will be the same as a
recent loan to Landlord or its affiliates by institutional construction and long
term permanent lenders for a loan of similar principal amount within the
previous three (3) year period, or if Landlord has not obtained such financing
within such three (3) year period, the most recent institutional loan to
Landlord of a similar principal amount; The Tenant's interest in said loans
shall also secure Tenant's Lease obligations by Tenant executing and delivering
to Landlord a pledge and first security interest in Tenant's interest in said
loans to Landlord, with the right by Landlord in the event of Tenant's
bankruptcy or assignment for the benefit of creditors, having the right to
offset Landlord's first mortgage loan obligation to Tenant against Tenant's
Lease obligations to Landlords; and (iii) to obtain any and all applicable
permits and approvals required under building, zoning and environmental laws,
codes, rules and regulations and other laws then affecting the use and
development of such land in order to construct the Expansion Building(s) in
accordance with all of the terms of this Lease.

         Further, notwithstanding any language to the contrary contained in this
Exhibit "R", in the event that Tenant's option as to the Expansion Building(s)
expires or has otherwise been terminated pursuant to the above provisions of
this Exhibit "R", then Landlord shall have, at any time thereafter during the
Term of this Lease, the right to construct the Expansion Building(s) (or any
portions thereof), elsewhere in the Park, and, subject to Tenant's Right of
First Refusal as set forth in Exhibit Q hereto, lease such space to any third
party upon such terms and conditions as are negotiated by Landlord in its sole
and absolute discretion, and Tenant shall have no further rights thereto.
Landlord and Tenant hereby further acknowledge and agree that in such event, the
Expansion Building(s) may be enlarged or reduced by Landlord in accordance with
applicable laws, codes, rules and regulations.

         VI. Notwithstanding Landlord's Expansion obligations as set forth in
this Exhibit "R", in the event that Landlord's mortgage lender institutes
foreclosure proceedings and/or becomes mortgagee in possession of the Building,
then Landlord's Expansion obligations hereunder shall be of no force and effect,
and Landlord's failure to comply with such Expansion obligations shall not
constitute a default by Landlord under the Lease until such time, if ever, as
such foreclosure proceedings and/or Landlord's lender's mortgagee in possession
status shall terminate and the immediate pre-foreclosure or pre-mortgagee in
possession Landlord again controls the Building. Further, should Landlord's
lender or anyone acquiring title to the property through it, either by deed in
lieu of foreclosure, foreclosure or otherwise, become Landlord, then such
Expansion option shall terminate.


                                       5

<PAGE>   146

                                   EXHIBIT "S"

                         Bedford Woods - BUILDING NO. 3
                                    SCHEDULE
--------------------------------------------------------------------------------
                 (Assumes Lease signed not later than 11/14/00)


RELEASE TENANT ARCHITECT                          (MARGULIES)         10/20/00

BASE BUILDING DESIGN EXTERIOR PLUS (3 weeks)                  10/3/00-10/20/00
      INTERIOR FLOOR PLANS ARCHITECTURE
      (BOTH BUILDINGS 3 AND 4)           (SMM)

TENANT PROGRAM DEVELOPMENT AND                                        11/15/00
      ESTIMATE OF ROOFTOP MECHANICAL
      EQUIPMENT LOAD FOR STEEL STRUCTURAL
      DRAWINGS & BUILDING ELECTRICAL LOAD

CONSTRUCTION SITE PLANS (SMM)                                        (4 weeks)
                                                               10/9/00-11/8/00

BUILDING STRUCTURAL DRAWINGS, BUILDING                                10/27/00
      PERMIT, AND MILL ORDER SET       (PATTI)

SITE WORK FOR FOUNDATIONS  (2 1/2 weeks)                     11/27/00-12/15/00
      (BALANCE SPRING AND SUMMER 2001)

BASE BUILDING MECHANICAL, ELECTRICAL,                                  11/6/00
      PLUMBING FOR BUILDING PERMIT       (SMM)

SUBMIT PLANS TO BUILDING INSPECTOR FOR                                11/14/00
      BUILDING PERMIT                    (SMM)

BUILDING INSPECTOR REVIEW & ISSUE PERMIT   (4 weeks ?)
                                                             11/14/00-12/12/00

STEEL AND PRECAST FABRICATION                                        (22 weeks)
                                                              11/15/00-4/23/01
      (AFTER LEASE EXECUTION)

11.   COMPLETE BASE BUILDING PLANS INCLUDING
                                                                        1/8/01
      ALL PARTITIONS, ELECTRICAL, PLUMBING, ETC.
      (BOTH BUILDINGS 3 AND 4)           (SMM)

LOCATE ALL MAJOR TENANT ROOF & SLAB                                     1/8/01
      PENETRATIONS (BOTH BUILDINGS 3 AND 4) (MARGULIES)

<PAGE>   147

13.   COMPLETE TENANT PLANS                                   (24 weeks)
                                                              10/16/00-3/30/01
      (BOTH BUILDINGS 3 AND 4)               (MARGULIES)

14.   STEEL AND PRECAST ERECTION PLUS ROOF  (16 weeks)        4/30/01-8/20/01
      AND WINDOWS

15.   FIRST FLOOR UNDERGROUND AND SLAB ?  (4 weeks)           6/11/01-7/11/01

16.   TENANT WORK                                             (25 weeks)
                                                              6/11/01-11/30/01
      (START ABOVE CEILING BEFORE ROOF AND WINDOWS)

BUILDING NO. 4 DELIVERED 3 MONTHS LATER, I.E.,  3/1/02.
                                               --------


<PAGE>   148

                                   EXHIBIT "T"

                                 NOTICE OF LEASE


       In accordance with the provisions of Massachusetts General Laws (Ter.
Ed.) Chapter 183, Section 4, as amended, notice is hereby given of a certain
lease (hereinafter referred to as the "Lease") dated as of November ___, 2000 by
and between Bedford Woods I Limited Partnership ("Landlord") and RSA Security,
Inc. (hereinafter referred to as "Tenant").

                              W I T N E S S E T H:

       1.     The address of the Landlord is c/o The Gutierrez Company, One Wall
              Street, Burlington, Massachusetts 01803.

       2.     The address of the Tenant is 20 Crosby Drive, Bedford,
              Massachusetts 01730 (prior to the Term Commencement Date) and
              Building 3, Bedford Woods, 174 Middlesex Turnpike, Bedford,
              Massachusetts 01730 (after the Term Commencement Date).

       3.     The Lease was executed on November __, 2000.

       4.     The Term of the Lease is a period of fifteen (15) years beginning
              on the Term Commencement Date determined in accordance with
              Section 3.2 of the Lease, currently scheduled for December 2,
              2001.

       5.     Subject to the provisions of the Lease, the Tenant has the option
              to extend the Term of the Lease for two (2) successive five (5)
              year terms pursuant to Exhibit "F" of the Lease.

       6.     The Tenant has an expansion option to lease up to 371,768 rentable
              square feet of additional space in Building 2 and Building 1 to be
              located on the property described in Exhibit B attached hereto.

       7.     The Lot and the Park, as such terms are defined in the Lease, are
              subject to the covenants and agreements contained in Exhibit "I"
              of the Lease.

       8.     The demised premises is one hundred eighty-eight thousand, two
              hundred twenty (188,220) rentable square feet located within a
              four (4) story building containing approximately one hundred
              eighty-eight thousand two hundred twenty (188,220) rentable square
              feet located at 174 Middlesex Turnpike, 3 Bedford Woods Drive,
              Bedford, Massachusetts 01730, and the areas of which are the
              subject of all appurtenant rights and easements set forth in
              Sections 2.1 and 10.14 of the Lease to be located on Lot 3 as
              further described on Exhibit A-1 attached hereto.

       9.     The deed for the real estate of which the demised premises under
              the Lease is a part was recorded on with the Middlesex North
              Registry of Deeds in Book _______, Page _____, as more
              particularly described in Exhibit "A" attached hereto.

<PAGE>   149


       This Notice of Lease has been executed merely to give notice of the
Lease, and all of the terms, conditions and covenants of which are incorporated
herein by reference. The parties hereto do not intend this Notice of Lease to
modify or amend the terms, conditions and covenants of the Lease which are
incorporated herein by reference.

       IN WITNESS WHEREOF, the parties hereto have duly executed this Notice of
Lease this ___ day of November, 2000.

                                   LANDLORD:
                                   BEDFORD WOODS LIMITED PARTNERSHIP I

                                   BY THE GUTIERREZ COMPANY
                                   ITS GENERAL PARTNER

                                   BY:
                                   ITS:

                                   DATED:

                                   TENANT:
                                   RSA SECURITY, INC.


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

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

                                   Dated:
                                         ---------------------------------------


                                       2

<PAGE>   150


                          COMMONWEALTH OF MASSACHUSETTS

MIDDLESEX, SS.                                               ____________, 2000


       Then personally appeared before me __________________, as trustee of and
acknowledged the foregoing instrument to be his free act and deed as trustee
aforesaid.


                                          --------------------------------------
                                          NOTARY PUBLIC
                                          My Commission Expires:


                          COMMONWEALTH OF MASSACHUSETTS

_______________, SS.                                         ____________, 2000


         Then personally appeared before me ________________, as
________________, and acknowledged the foregoing instrument to be his/her free
act and deed as _________ aforesaid.


                                          --------------------------------------
                                          NOTARY PUBLIC
                                          My Commission Expires:


                                       3
<PAGE>   151


                                  EXHIBIT "A-1"


       A certain parcel of land located on Middlesex Turnpike in the Bedford
Woods Office Park, Bedford, Massachusetts shown as Lot 1-3 on that certain plan
entitled "Plan of Land in Bedford, MA prepared for The Gutierrez Company"
prepared by Hancock Survey Associates, Inc. Scale 1" = 100' dated November 13,
2000 and to be recorded with the Middlesex South Registry of Deeds when executed
by the Town of Bedford, Massachusetts Planning Board. Said Lot 1-3 contains
approximately 31.1611 acres according to said plan (a copy of which is attached
hereto and made a part hereof). Landlord and Tenant hereby acknowledge and agree
that this Exhibit A-1 shall be replaced by amendment to this Notice of Lease
upon creation of the Lot and recording of said plan. Landlord and Tenant agree
not to record this Notice of Lease until said plan is recorded in the Middlesex
South Registry of Deeds.



<PAGE>   152



                                   EXHIBIT "B"


       Certain parcels of land located on Middlesex Turnpike in the Bedford
Woods Office Park, Bedford, Massachusetts shown as Lots 1 and 2on that certain
plan entitled "Plan of Land in Bedford, MA prepared for The Gutierrez Company"
prepared by Hancock Survey Associates, Inc. Scale 1" = 100' dated November 13,
2000 and to be recorded with the Middlesex South Registry of Deeds when executed
by the Town of Bedford, Massachusetts Planning Board. Said Lot 1-1 contains
approximately 12.1035 acres and Lot 1-2 contain approximately 10.2574 acres
according to said plan (a copy of which is attached hereto and made a part
hereof). Landlord and Tenant hereby acknowledge and agree that this Exhibit A-1
shall be replaced by amendment to this Lease upon creation of the Lots and
recording of said plan.