<PAGE>

                                                                    Exhibit 10.5


                                 LEASE AGREEMENT

                                     Between

                          RAD DATA COMMUNICATIONS, INC.

                                   "Landlord"


                                      -and-

                                 RADVISION, INC.

                                    "Tenant"



                               575 Corporate Drive
                            Mahwah, New Jersey 07430



<PAGE>


                                TABLE OF CONTENTS

<TABLE>
<CAPTION>
ARTICLE NO.                            DESCRIPTION                                                PAGE
----------                             -----------                                                ----
<S>          <C>                                                                                  <C>
                                   Basic Lease Provisions

I            Demised Premises                                                                     7
II           Term                                                                                 7
III          Rent                                                                                 8
IV           Use and Occupancy                                                                    9
V            Alterations or Improvements by Tenant                                                10
VI           Maintenance                                                                          11
VII          Compliance with Laws, Indemnity and Insurance                                        12
VIII         Subordination and Estoppel                                                           13
IX           Destruction - Fire or Other Casualty                                                 14
X            Mutual Waiver of Subrogation                                                         14
XI           Condemnation and Other Proceedings                                                   15
XII          Assignment and Subletting                                                            16
XIII         Surrender                                                                            18
XIV          Holding Over                                                                         18
XV           Landlord's Right of Entry                                                            19
XVI          Default                                                                              19
XVII         Landlord's Rights Upon Tenant's Default                                              20
XVIII        Landlord's Remedies Cumulative: Expenses                                             21
XIX          No Waiver                                                                            22
XX           Landlord's Reserved Rights                                                           23
XXI          Landlord's Liability                                                                 23
XXII         Tenant's Liability                                                                   24
XXIII        Tenant's Insurance                                                                   25
XXIV         Mechanic's Liens                                                                     26
XXV          Quiet Enjoyment                                                                      26
XXVI         Relocation of Tenant                                                                 26
XXVII        Landlord's Services                                                                  27
XXVIII       Additional Rent                                                                      28
XXIX         Personal Property Taxes                                                              29
XXX          Security Deposit                                                                     30
XXXI         Use of Security Deposit                                                              30
XXXII        Definition of Landlord                                                               30
XXXIII       Notices                                                                              31
XXXIV        Signs                                                                                31
XXXV         Notice of Defects and Accidents                                                      31
XXXVI        Rules and Regulations                                                                32
XXXVII       Directory                                                                            32
XXXVIII      Hazardous Materials and Compliance
                          with Environmental Laws                                                 32
XXXIX        Miscellaneous                                                                        34
</TABLE>

                                       2

<PAGE>

<TABLE>
<S>        <C>           <C>                                                                      <C>
EXHIBITS   EXHIBIT A:    The Premises                                                             41
           EXHIBIT B:    Landlord's Work
                         in the Premises                                                          42
           EXHIBIT C:    Rules and Regulations                                                    43
</TABLE>

                                       3

<PAGE>


                             BASIC LEASE PROVISIONS

                                     of the

                                 LEASE AGREEMENT

                                     between

                   RAD DATA COMMUNICATIONS, INC., as Landlord,

                                       and

                           RADVISION, INC., as Tenant.

The following basic terms of the Lease (hereinafter referred to as the "Basic
Lease Provisions") between Landlord and Tenant are an integral part of and are
incorporated by reference into the within Lease:

A. The "Building":          575 Corporate Drive, Mahwah, New Jersey 07430
                            comprising  approximately  144,570 rentable
                            square feet.  The foregoing  land and building
                            shall  sometimes be referred to herein as the
                            "Real Property".

B. The "Premises":          (1) The Premises is known as Suite 420 in Lobby 4
                            and is depicted on the Floor Plan attached hereto
                            as Exhibit "A" and consists of approximately
                            2,148 rentable square feet.

C. The "Term":              (1) The Term of this Lease shall be five (5) years
                            beginning on May 12, 1997 (the Commencement Date")
                            and ending May 11, 2002 (the "Expiration Date").

D. The "Basic Rent":        (1) Annual Base Rent: $21,480 Net
                            (2) Monthly  Installments of Base Rent: $1,790 Net
                            plus Tenant  utilities and other pass throughs,
                            as set f'orth in the Lease.

E. Tenant's Proportionate Share:        1.49%

F. The Security Deposit:                NONE

G.  Broker(s):                          NONE


                                       4

<PAGE>


H.  Addresses for Notice
    and Payments:            (1) Landlord:

                             RAD Data Communications, Inc.
                             900 Corporate Drive
                             Mahwah, New Jersey 07430
                             ATTN: Comptroller
                             cc: Real Estate Management Co.
                             155 North Dean Street
                             Englewood, NJ 07631

                             Donald N. Render, Esq.
                             10 S. Franklin Turnpike
                             Suite 205, P.O. Box 630
                             Ramsey, NJ 01446

                             (2) Tenant:

                             RADVISION, INC.
                             575 Corporate Drive
                             Mahwah, New Jersey 07430

                             (3) Checks Payable to:

                             R.E. Mgt Co. - 575 Special

                             Mail Payments to:

                             Real Estate Management Company
                             155 North Dean Street
                             Englewood, NJ 07631

I. Use:

                SIC Number:  ________

J. Landlord's Work:           As set forth on Exhibit "B" attached hereto. The
                              work shall specifically  including the following:

                                       5

<PAGE>


                                As Delivered.

                              All of Landlord's Work shall commence upon the
                              execution of this Lease and shall diligently
                              proceed to completion. Said Landlord's Work shall
                              be performed in accordance with all applicable
                              local, state and Federal building laws,
                              regulations and standards. Landlord shall procure
                              at its sole cost and expense all necessary permits
                              to commence and to complete the Landlord's Work.

K. Cleaning:                  Tenant shall be responsible for  cleaning its own
                              premises

L. Parking:                   Seven (7) Parking Spaces

M. Net Lease
   Additional Rent:           The Base Rent shown above shall be net-net; the
                              Tenant will be required to pay 1.49% of all Real
                              Estate Taxes (as defined in Article 28.2 herein),
                              together with 1.49% of the Landlord's Operating
                              Costs (as defined in Article 28.4 herein). Such
                              payments shall be made monthly by Tenant with the
                              Base Rent, as billed by the Landlord and as more
                              particularly set forth in the Lease. In addition,
                              the Tenant will be required to pay its Tenant
                              Electric and Gas at a rate of $1.25 per rentable
                              square foot, which is $2,685 per annum, subject to
                              revisions based on a survey of usage or gross
                              amount negotiated by Landlord and Tenant.


Approved by Landlord:                       Approved by Tenant:

RAD Data Communications, Inc.               RADVISION, Inc.



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

                                       6

<PAGE>


 THIS AGREEMENT OF LEASE (this "Lease") dated as of May 12, 1997, between RAD
Data Communications, Inc., a New Jersey Corporation, (hereinafter referred to as
"Landlord"), and RADVISION, Inc. (hereinafter referred to as "Tenant").

                              W I T N E S S E T H:

Landlord and Tenant hereby covenant and agree as follows:

                                    ARTICLE I
                                Demised Premises

      1.1 Landlord hereby leases to Tenant and Tenant hereby leases from
Landlord for the term and upon the terms, conditions, covenants and agreements
hereinafter provided, the Premises. The Premises consist of space which: (i) is
located on the floor or floors of the Building as is specified in Item B(1) of
the Basic Lease Provisions, (ii) is located in one or more areas or parts of
each such floor, and (iii) is bounded by the proposed or existing demising walls
therefor, the approximate locations of such demising walls and space being
marked in color or crosshatched and shown on the diagram(s) of the floor plan
for each such floor, such diagram(s) being attached to this Lease as Exhibit A
and made a part hereof. The Premises is to be known and called by the Suite
Number or Numbers specified in Item B(1) of the Basic Lease Provisions. The
appropriate number of rentable square feet contained in the Premises, as
determined by Landlord, for identification purposes only, is specified in Item
B(1) of the Basic Lease Provisions (the "Rentable Area"). The lease of the
Premises includes the right, together with other tenants of the Building and
members of the public, to use the common public areas of the Building, but
includes no other rights not specifically set forth herein. Landlord shall
finish the Premises as set forth in Exhibit B attached hereto and made a part
hereof. It is understood and agreed that Landlord will not make and is under no
obligation to make, any alterations, decorations, additions or improvements in
or to the Premises, structural or otherwise, except as set forth in Exhibit B.
Landlord agrees to deliver possession of the Premises to Tenant and Tenant
agrees to accept the same from Landlord, upon written notice from Landlord to
Tenant, that Landlord's work in the Premises described in Exhibit B has been
substantially completed.


                                   ARTICLE II
                                      Term

      2.1 The Premises are leased for the period of years and months as
specified in Item C of the Basic Lease Provisions to commence at 12:01 A.M. on
the Commencement Date and to end at 11:59 P.M. on the Expiration Date unless the
Term

                                       7

<PAGE>


shall sooner terminate pursuant to any of the terms, covenants or conditions of
this Lease or pursuant to law.

      2.2 Notwithstanding anything in 2.1 to the contrary, if, on or prior to
the Commencement Date of the Term, the premises are not ready for occupancy,
this Lease shall nevertheless continue in full force and effect and Tenant shall
have no right to rescind, cancel or terminate same nor shall Landlord be liable
for damages, if any, sustained by Tenant by reason of inability to obtain
possession thereof on such date. In such event, Landlord shall give to Tenant,
written notice at least fifteen (15) days in advance of the date when Landlord
expects the Premises to be ready for occupancy by Tenant which date shall then
become the revised Commencement Date. The Term shall end on the revised
Expiration Date, which date shall be the same number of days after the revised
Commencement Date as it was after the original Commencement Date, unless sooner
terminated pursuant to any of the terms, covenants or conditions of this Lease
or pursuant to law.

      2.3 Then Tenant takes possession of the premises, Tenant shall be deemed
to have accepted the premises as being satisfactory and in good condition as of
the date of such possession.

                                   ARTICLE III
                                      Rent

      3.1 Tenant covenants and agrees to pay to Landlord as rent for and during
the Term hereof the annual sum as specified in Item D(1) of the Basic Lease
Provisions as Basic Rent.

      3.2 Basic Rent and any Additional Rent payable pursuant to the provisions
of this Lease shall be payable by Tenant to Landlord with payment made to Real
Estate Management Company and sent to 155 Dean Street, Englewood, NJ 07631 (or
at such other place as Landlord may designate in a notice to Tenant) in lawful
money of the United States without prior demand therefor and without any offset
or deduction whatsoever except as otherwise specifically provided in this Lease
for the convenience of Tenant. Basic Rent shall be payable in equal monthly
installments in the amount of $1,790.00, in advance, on the first (1st) day of
each month during the Term. The installment of Basic Rent for the first (1st)
full calendar month of the Term, is due and payable by Tenant to Landlord at the
time of the execution and delivery of this Lease. In the event that the
Commencement Date shall occur on a date other than the first (1st) day of any
calendar month, Tenant shall pay to Landlord on the first (1st) day of the month
next succeeding the month during which the Commencement Date shall occur, a sum
equal to $1,790.00, divided by thirty (30) then multiplied by the number of
calendar days in the period from the commencement Date to the last day of the


                                       8

<PAGE>


month in which the Commencement Date shall occur, both inclusive. Such payment,
together with the sum paid by Tenant upon execution of this Lease, shall
constitute payment of the Basic Rent for the period from the Commencement Date
to and including the last day of the next succeeding calendar month.

      3.3. Tenant covenants to pay Basic Rent and any Additional Rent payable
pursuant to the provisions of this Lease and to observe and perform and to
permit no violation of the terms, covenants and conditions of this Lease on
Tenant's part.

                                   ARTICLE IV
                                Use and Occupancy

      4.1 Tenant shall use and occupy the Premises solely for general office use
and only in accordance with the uses permitted under applicable zoning and other
municipal regulations. Without the prior written consent of Landlord, the
Premises shall not be used for any other purpose, or for any purpose that will
constitute a nuisance or unreasonable annoyance to Landlord or other tenants of
the Building and shall comply with all present and future laws, ordinances,
regulations, and orders of the United States of America, the jurisdiction in
which the Building is located, and any other public or quasi-public authority
having jurisdiction over the Premises. It is expressly understood that if any
law, ordinance, regulation or order requires an occupancy permit for the
Premises, Landlord shall obtain such permit at Landlord's own expense (that is
to say, Landlord will pay the cost of the application for the issuance of the
Certificate of Occupancy).

      4.2 Landlord has adopted a policy prohibiting smoking within the Entire
Premises. Tenant hereby acknowledges that Tenant, Tenant's employees, agents and
invitees are not permitted to smoke anywhere within the Premises or Entire
Premises.

      4.3 In addition to the parking spaces provided to Tenant under paragraph L
as set forth in the Basic Lease Provisions, supra, Tenant shall have the right
to the non-exclusive use of the parking lot on the Real Property (as defined in
paragraph 5.1) for all employees and visitors. The same right has been or will
be given to all other tenants in the Building, and to their respective
employees, agents, customers and invitees and to other persons, and it does not
entitle Tenant or other tenants to any particular assigned spaces in the parking
lot. Tenant covenants and agrees to comply with all reasonable rules and
regulations which Landlord may hereafter from time to time or at any time make
pursuant to the terms of Article XXXVI to assure exclusive use of designated
parking spaces on the Real Property by permitted users. Landlord's remedies
under such rules and regulations may include, but shall not be limited to, the
right to tow away at owner's expense any vehicles not parked in compliance with
these rules and regulations. Landlord shall not be responsible to Tenant for the
non-


                                       9

<PAGE>



compliance or breach by any other tenant of said rules and regulations,
provided, however, Landlord agrees to use reasonable efforts to enforce such
rules and regulations uniformly.

                                    ARTICLE V
                      Alterations or Improvements by Tenant

      5.1 Tenant shall make no changes in or to the Premises of any nature
without Landlord's prior written consent not to be unreasonably withheld or
delayed, except that Tenant may make immaterial and decorative changes to the
Premises without the Landlord's prior written consent. Subject to the prior
written consent of Landlord, Tenant, at Tenant's sole expense, may hire
contractors approved by Landlord to make alterations, installations, additions
or improvements in or to the Premises (collectively hereinafter referred to as
the "Alterations") which are non-structural and which do not affect utility
services, plumbing or electrical lines in or to the Premises or the Building.
The Alterations shall, upon installation, become the property of Landlord and
shall remain upon and be surrendered with the Premises, unless Tenant by written
notice to Landlord no later than thirty (30) days prior to the Expiration Date
requests Landlord's consent to remove same. If Landlord so consents the
Alterations shall be removed from the Premises by Tenant prior to the Expiration
Date at Tenant's sole expense. Nothing in this Article V shall be construed to
give Landlord title to or to prevent Tenant's removal of trade fixtures,
moveable office furniture and equipment, but upon removal of any such from the
Premises or upon removal of any other installation as may be permitted by
Landlord, Tenant shall immediately and at its expense, repair and restore the
Premises to the condition existing prior to the Alterations. Tenant shall repair
any damage to the Premises, the Building, or the real property on which the
Building is located (hereinafter collectively referred to as the "Real
Property") incurred during such removal. All property permitted or required to
be removed by Tenant at the Expiration Date or sooner termination of the Term
which remains on the Premises after the Expiration Date or sooner termination of
the Term shall be deemed abandoned and may, at the election of Landlord, either
be retained as Landlord's property or may be removed from the Premises by
Landlord at Tenant's expense. If Tenant does not repair or restore said damage
Landlord is entitled to deduct said cost and expense from Tenant's security
deposit.

      5.2 Prior to the commencement of the Alterations, Tenant shall at its sole
expense, obtain all required permits, approvals and certificates required by all
Governmental Authorities and upon completion of the Alterations, certificates of
final approval thereof. Tenant shall deliver duplicates of same to Landlord
promptly upon their receipt. Tenant shall carry and will cause Tenant's
contractors and subcontractors to carry such worker's compensation, general
liability, personal and property damage


                                       10

<PAGE>


insurance as required by law and in amounts no less than the amounts set forth
in Article XXIII hereof.

      5.3 As a condition precedent to the written consent of Landlord, Tenant
agrees to obtain and deliver to Landlord written and unconditional waivers of
mechanics' and materialmen's liens upon the Real Property or a part, for all
work, labor and services to be performed, and materials to be furnished, by them
in connection with such work, signed by all contractors, subcontractors,
materialmen and laborers to be involved in such work. If, notwithstanding the
foregoing, any mechanic's or materialmen's lien is filed against the Real
Property, for work claimed to have been done for, or materials claimed to have
been furnished to, Tenant, such lien shall be discharged by Tenant within ten
(10) days thereafter, at Tenant's sole cost and expense, by the payment thereof
or by filing any bond required by law. If Tenant shall fail to discharge any
such mechanic's or materialmen's lien, Landlord may, at its option, discharge
the same and treat the cost thereof as Additional Rent payable with the monthly
installment of rent next becoming due; it being hereby expressly covenanted and
agreed that such discharge by Landlord shall not be deemed to waive or release
the default of Tenant in not discharging the same. It is understood and agreed
by Landlord and Tenant that any alterations, decorations, additions or
improvements shall be constructed on behalf of Tenant and that in the event
Landlord gives its written consent to Tenant's making any such alterations,
decorations, additions or improvements, such written consent shall not be deemed
to be an agreement or consent by Landlord to subject Landlord's interest in the
Premises, the Building or the Real Property to any mechanic's or materialmen's
liens which may be filed in respect to any such work done by or on behalf of
Tenant.

      5.4 Tenant shall indemnify and hold Landlord harmless from and against any
and all expenses, liens, claims or damages to person or property which arise
directly or indirectly by reason of the Alterations, structural or otherwise,
made by Tenant without the prior written consent of Landlord. Landlord shall
have the right to remove same and Tenant shall be liable for any and all
expenses incurred by Landlord in said removal and subsequent restoration of the
Premises to the original condition.

      5.5 In any case where Landlord's consent is required pursuant to this
Article V, such consent shall not be unreasonably withheld or delayed.

                                   ARTICLE VI
                                   Maintenance

      6.1 Tenant shall take good care of the Premises throughout the Term and
preserve same in the condition delivered to Tenant on the Commencement Date,
normal wear and tear and damage by fire or other casualty not caused by Tenant,
excepted. Tenant


                                       11

<PAGE>


further agrees not to injure, overload, deface or commit waste of the Premises.
Tenant shall be responsible for all injury or damage of any kind or character to
the Real Property, including the windows, floors, walls, ceilings, lights,
electrical equipment and HVAC equipment, caused by Tenant or by anyone using or
occupying the Premises by, through or under Tenant. Landlord shall repair the
same and Tenant shall pay the costs incurred therefor to Landlord immediately
upon demand plus a ten (10%) management fee. If the Premises become infested
with vermin, Tenant shall, at Tenant's expense, cause the same to be
exterminated from time to time to the satisfaction of Landlord and shall employ
such exterminators as shall be approved by Landlord (except if resulting from
Landlord or other tenants, in which case Landlord shall be liable for the cost
thereof).

      6.2 Landlord will operate, maintain and repair the "Common Facilities"
which may be provided pursuant to this Article.

      6.3 For the purposes of this Lease, "Common Facilities" shall mean
facilities which may be provided by the Landlord in the Building or Real
Property for the general common use or benefit to Tenant or other tenants,
including, without limitation, all parking areas, access roads, employee parking
areas, driveways, pedestrian sidewalks, hallways for some or all Tenants,
reception areas for some or all Tenants and ramps, landscaped and planted areas,
walls, retaining walls, foundation, roof, stairways, fire escapes, lighting
facilities, comfort stations and other similar areas and improvements. The
Common Facilities shall at all times be subject to the exclusive control and
management of Landlord. Landlord shall have the right to establish, modify and
enforce reasonable rules and regulations with respect to the Common Facilities;
to change the areas, locations and arrangements of parking areas and other
Common Facilities; to enter into, modify and terminate easement and other
agreements pertaining to the use and maintenance of the parking areas and other
Common Facilities.

      6.4 Landlord reserves the right in its sole discretion, to change,
rearrange, alter, modify, reduce or supplement any or all of the Common
Facilities so long as adequate facilities are made available to the Tenant.

                                   ARTICLE VII
                  Compliance with Laws, Indemnity and Insurance

      7.1 Tenant shall not do, or permit anything to be done in or to the
Premises, or bring or keep anything therein which will, in any way, increase the
cost o f fire or public liability insurance on the Real Property, or invalidate
or conflict with the fire insurance or public liability insurance policies
covering the Real Property, the Building, fixtures or any personal property kept
therein, or obstruct or interfere with

                                       12

<PAGE>


the rights of Landlord or of other tenants, or in any other way injure or annoy
Landlord or other tenants, or subject Landlord to any liability for injury to
persons or damage to property, or interfere with the good order of the Building,
or conflict with the present or future laws, rules or regulations of any
Governmental Authority. Tenant hereby indemnifies and shall hold Landlord
harmless of and from all liability for injury to persons or damage occurring on
the Premises or in the Building or on the Real Property occasioned by any act or
omission of Tenant, or Tenant's agents, servants, employees, invitees or
licensees excluding Landlord's gross negligence or willful misconduct. Tenant
agrees that any increase in fire and casualty insurance premiums on the Building
or contents caused by the occupancy of Tenant and any expense or cost incurred
in consequence of negligence, carelessness or willful action of Tenant, Tenant's
agents, servants, employees, invitees or licensees, shall be reimbursed to
Landlord with ten (10) days of demand therefor. Landlord shall have all the
rights and remedies for the collection of same as are conferred upon Landlord
for the collection of Basic Rent provided to be paid pursuant to the terms
hereof,

                                  ARTICLE VIII
                           Subordination and Estoppel

      8.1 Tenant agrees that this Lease is subject and subordinate to all ground
or underlying leases and to the lien of any mortgages or deeds of trust now on
or which at any time in the future that may be made a lien upon the Real
Property, and to all advances made or hereafter to be made upon the security
thereof. This subordination provision shall be self-operative and no further
instrument of subordination shall be required, provided, however, that Tenant
agrees to execute and deliver within five (5) business days, upon request, such
further instrument or instruments confirming this subordination as shall be
desired by Landlord or by any mortgagee or proposed mortgagee of the Real
Property; and Tenant hereby constitutes and appoints Landlord as Tenant's
attorney-in-fact to execute any such instrument or instruments. Tenant further
agrees that at the option of the holder of any mortgage or of the trustee under
any deed of trust securing the Real Property, this Lease may be made superior to
said mortgage or deed of trust by the insertion therein of a declaration that
this Lease is superior. Landlord shall make its best efforts to procure from any
future Mortgagee, a Non-Disturbance Agreement which shall comprise the
Mortgagee's recognition of Tenant's peaceful possession of the subject premises
pursuant to the terms of this Lease, so long as the Tenant is not in default
under the Lease provisions.

      8.2 Tenant agrees at any time and from time to time upon not less than
five (5) business days' prior written request by Landlord, to execute,
acknowledge and deliver to Landlord a statement in writing certifying that this
Lease is unmodified and in full force and effect (or, if there have been
modifications, that the same are in full force and effect as modified) and
stating the modifications, that there are no offsets,


                                       13

<PAGE>


defenses, defaults, or counterclaims under this Lease or against Landlord, the
dates to which the Basic Rent and Additional Rent have been paid in advance, if
any, it being intended that any such statement delivered pursuant to this
paragraph 8.2 may be relied upon by a prospective purchaser of Landlord's
interest or a mortgagee of Landlord's interest or assignee of any mortgage upon
Landlord's interest in the Real Property.

                                   ARTICLE IX
                      Destruction - Fire or Other Casualty

      9.1 If the Premises or the Building shall be damaged by fire or other
casualty; (i) except as otherwise provided in subsection (ii) hereof, the damage
shall be repaired by and at the expense of Landlord and until such repairs shall
be made the Basic Rent and Additional Rent shall be equitably abated according
to the part of the Premises which is usable by Tenant. Landlord agrees, at its
expense, to repair promptly any damage to the Premises, except that Tenant
agrees to repair or replace its own furniture, furnishings and equipment. No
penalty shall accrue due to a delay caused by strike, lockout, act of God,
inability to obtain labor or materials, governmental restrictions, enemy
actions, civil commotion, fire, unawardable casualty or any other cause similar
or dissimilar beyond the reasonable control of either Landlord or Tenant or due
to the passing of time while waiting for an adjustment of insurance proceeds
(hereinafter referred to as an "Excusable Delay"); (ii) If the Premises are
totally damaged or are rendered wholly untenantable by fire or other casualty,
or if Landlord's architect certifies that it cannot be repaired within ninety
(90) days of the casualty or if Landlord shall decide not to restore or repair
the same, or shall decide to demolish the Building, or not to rebuild the
Building or the Premises, then Landlord shall, within ninety (90) days after
such fire or other casualty, give Tenant a notice of such decision, and
thereupon the Term shall expire ten (10) days after such notice is given, and
Tenant shall vacate the Premises and surrender the same to Landlord; (iii) If
Landlord fails to complete the repair and restoration of the Premises within one
hundred twenty (120) days from the date of the casualty (subject to Excusable
Delays) then Tenant shall have the right to cancel and terminate this Lease upon
the delivery of a notice to Landlord delivered within fifteen (15) days after
the expiration of the aforesaid one hundred twenty (120) days period; (iv)
Landlord agrees that it shall diligently pursue all repair and restoration work
required on its part to be completed hereunder.

                                    ARTICLE X
                          Mutual Waiver of Subrogation

      10.1 Landlord hereby waives any and all rights of recovery against Tenant
for or arising out of damage to or destruction of the Premises, the Building, or
the Real


                                       14

<PAGE>


Property and any other property of Landlord from causes then insured under
standard fire and extended coverage insurance policies or endorsements to the
extent that its insurance policies then in effect permit such waiver, and Tenant
hereby waives any and all rights of recovery against Landlord for or arising out
of damage to or destruction of the Premises, the Building or the Real Property
and any property of Tenant from causes then insured under standard fire and
extended coverage insurance policies to the extent that its insurance policies
then in effect permit such waiver. If at any time during the Term any insurance
carrier which shall have issued a policy to either of the parties covering the
Real Property, the Premises, the Building or any of the property of Tenant,
shall refuse to consent to the waiver of the right of recovery with respect to
any loss payable under such policy, or if such carrier shall consent to such
waiver only upon the payment of an additional premium (unless such additional
premium is voluntarily paid by one of the parties hereto) or shall cancel a
consent previously given, or shall cancel or threaten to cancel any policy
previously issued and then in full force and effect, then in any such event, the
waiver in this paragraph 10.1 shall thereupon be of no further force and effect
as to the loss, damage or destruction covered by such Policy except as
hereinafter provided. If, however, at any time thereafter such consent shall be
obtained therefor from any existing or any substitute insurance carrier, the
waiver hereinabove provided for shall again become effective.

                                   ARTICLE XI
                       Condemnation and Other Proceedings

      11.1 If substantially all of the Premises shall be acquired or condemned
by eminent domain proceedings, or by giving of a deed in lieu thereof, or shall
be ordered demolished or unfit for present use by any governmental body, then
and in that event, the Term shall cease and terminate from the date of
title-vesting or final order pursuant to such proceeding or agreement. If a
partial taking of the Premises or the Building shall be so ordered, acquired or
condemned but Tenant is able to reasonably conduct its business at the Premises
consistent with its Permitted Use as set forth in Article IV hereinabove, this
Lease shall cease and terminate Landlord's option, and if such option is not
exercised by Landlord, an equitable adjustment of the Basic Rent and Additional
Rent payable by Tenant for the remaining useable portion of the Premises shall
be made. In the event of a termination under this Article Xl, Tenant shall have
no claim against Landlord for the value of any unexpired Term and Tenant shall
have no claim against Landlord, other than for the adjustment of the Basic Rent
and Additional Rent as hereinbefore mentioned, or be entitled to any portion of
any amount that may be awarded as damages or paid as a result of such
proceedings or as the result of any agreement made by any governmental authority
with Landlord.

      11.2 Tenant may, if allowed by statute, seek such awards or damages for
moving expenses, loss of profits and fixtures and other equipment installed by
it (if any) which


                                       15


<PAGE>


do not, under the terms of this Lease, become the property of Landlord at the
termination hereof. Such awards or damages must be made by a condemnation court
or other authority and must be separate and distinct from any award to Landlord
for the Real Property and Building and shall not diminish any award of Landlord.
For purposes of this paragraph 11.2, a substantial part of the Premises shall be
considered to have been taken if Tenant is not reasonably able to conduct its
business at the Premises consistent with its permitted use as set forth in
Article IV hereinabove or more than thirty percent (30%) of the Premises are
unusable by Tenant as a direct result of such taking.

                                   ARTICLE XII
                            Assignment and Subletting

      12.1 Tenant for itself, its heirs, distributees, successors and assigns,
expressly covenants that it shall not by operation of law or otherwise assign,
mortgage or encumber this Lease, or any part thereof, or permit the premises to
be used by others without the prior written consent of Landlord in each
instance. Any attempt to do so by Tenant shall be void. The consent by Landlord
to any assignment, mortgage, encumbrance, subletting or use of the Premises by
others, shall not constitute a waiver of Landlord's right to withhold its
consent to any other assignment, mortgage, encumbrance or use of the Premises by
others. Without the prior written consent of Landlord, this Lease and the
interest of Tenant therein or any assignee of Tenant therein, shall not pass by
operation of law, and shall not be subject to garnishment or sale under
execution in any suit or proceeding which nay be brought against or by Tenant or
any assignee of Tenant.

      12.2 Landlord covenants and agrees that it will not unreasonably withhold
its consent to Tenant's assigning or subletting all or a part of the Premises;
provided, however, that Tenant shall not be in default under any of the terms,
covenants, conditions, provisions and agreements of this Lease at the time of
any notice or request for consent under the terms of this Article XII or at the
effective date of such subletting or assigning.

      12.3 (a) If Tenant requests Landlord's consent to an assignment of this
Lease or a subletting of all or any part of the Premises, Tenant shall submit to
Landlord:

       (1)  the sum of one thousand dollars ($1,000.00) as a non refundable fee
            to process each such request;

       (2)  the name of the proposed assignee or subtenant;

       (3)  the terms of the proposed assignment or subletting;


                                       16

<PAGE>


       (4)  the nature of the proposed subtenant's or assignee's business; and

       (5)  such information as to the proposed subtenant's or assignee's
            financial responsibility and general reputation as Landlord may
            reasonably require.

       (b) Upon the receipt of such request and information from Tenant,
Landlord shall have the option, to be exercised in writing within thirty (30)
days after such receipt, to either (1) cancel and terminate this Lease as of the
date of the notice if the request is to assign this Lease or to sublet all of
the Premises or, (2) if the request is to sublet a portion of the Premises only,
to cancel and terminate this Lease with respect to such portion, as of the date
set forth in Landlord's notice of exercise of such option; or (3) to grant said
request.

       (c) In the event Landlord shall cancel this Lease, Tenant shall surrender
possession of the Premises, or the portion of the Premises which is subject of
the request, as the case may be, on the date set forth in such notice in
accordance with the provisions of this Lease relating to surrender of the
Premises. If the Lease shall be canceled as to a portion of the Premises only,
the Basic Rent and Additional Rent payable by Tenant hereunder shall be reduced
proportionately according to the ratio that the number of rentable square feet
in the portion of space surrendered bears to the rentable square feet in the
Premises.

       (d) In the event that Landlord shall consent to a sublease or assignment
pursuant to the request from Tenant, Tenant shall cause to be executed by its
assignee or subtenant an agreement to perform faithfully and to assume and be
bound by all of the terms, covenants, conditions, provisions and agreements of
this Lease for the period covered by the assignment or sublease and to the
extent of the space sublet or assigned. An executed copy of each sublease or
assignment and assumption of performance by the sublessee or assignee, on
Landlord's standard form, shall be delivered to Landlord within five (5) days
prior to the commencement of occupancy set forth in such assignment or sublease.
No such assignment or sublease shall be binding on Landlord until Landlord has
received such copies as required herein.

       (e) In the event that Landlord shall consent to a sublease or assignment
pursuant to the request from Tenant, and such agreement shall be executed and go
into effect, and Tenant realizes a profit from such agreement, Tenant agrees to
pay to Landlord 100% of said profit. Profit is defined as any amount in excess
of amount that Tenant pays to Landlord as defined in Article III and Article
XXVIII of this Lease, less the reasonable cost of subletting the space; i.e.,
brokerage, advertisement, etc.

                                       17

<PAGE>


      12.4 In no event shall any assignment or subletting to which Landlord may
consent, release or relieve Tenant from its obligations to fully perform all of
the terms, covenants and conditions of this Lease on its part to be performed.

                                  ARTICLE XIII
                                    Surrender

      13.1 Upon the Expiration Date or sooner termination of the Term, Tenant
shall peaceably and quietly quit and surrender to Landlord the Premises, broom
clean, in as good condition as they were on the Commencement Date ordinary wear
and tear, repairs and replacements by Landlord, loss by fire, casualty and other
causes beyond Tenant's control, and alterations, additions and improvements
permitted hereunder, excepted. Tenant's obligation to observe or perform this
covenant shall survive the Expiration Date or prior expiration of the Term. If
the Expiration Date falls on a Sunday or a legal holiday, this Lease shall
expire at 12 noon on the business day first preceding said date.

                                   ARTICLE XIV
                                  Holding Over

         14.1 If Tenant holds possession of the Premises beyond the Expiration
date or prior expiration of the Term, Tenant shall become a tenant from
month-to-month at DOUBLE the Basic rent and Additional Rent payable hereunder
and upon all other terms and conditions of this lease, and shall continue to be
such month-to-month tenant until such tenancy shall be terminated by Landlord or
Tenant and such possession shall cease. Nothing contained in this Lease shall be
construed as a consent by Landlord to the occupancy or possession by Tenant of
the premises beyond the Expiration Date or prior expiration of the Term, and
Landlord, upon such Expiration date or prior expiration of the Term shall be
entitled to the benefit of all legal remedies that now may be in force or may be
hereafter enacted relating to the speedy repossession of the Premises and to all
damages to which Landlord is entitled.

                                   ARTICLE XV
                            Landlord's Right of Entry

      15.1 Landlord and Landlord's agents and representatives upon reasonable
prior notice to tenant shall have the right to enter into or upon the Premises,
or any part thereof, at all reasonable hours for the following purposes:

       (1)  examining the Premises;

                                       18

<PAGE>


       (2)  making such repairs or alterations therein as may be necessary in
            landlord's sole judgment for the safety and preservation thereof;

       (3)  erecting, maintaining, repairing or replacing wires, cables,
            conduits, vents or plumbing equipment running in, to or through the
            Premises; or

       (4)  showing the Premises to prospective new tenants (only during the
            last year of the Term), purchasers or mortgagees.

      15.2 Landlord may enter upon the Premises at any time in case of emergency
without prior notice to Tenant.

      15.3 Landlord, in exercising any of its rights under this Article XV,
shall not be deemed guilty of an eviction, partial eviction or disturbance of
Tenant's use or possession of the Premises and shall not be liable to Tenant for
same.

      15.4 All work performed by or on behalf of Landlord in or on the Premises
pursuant to this Article XV shall be performed with as little inconvenience to
Tenant's business as possible, and in such manner as not reasonably to interfere
therewith.

                                   ARTICLE XVI
                                     Default

      16.1 Each of the following, whether occurring before or after the
Commencement Date, shall be deemed a Default by Tenant and a breach of this
Lease:

     (a)   the filing of a petition by or against Tenant for adjudication as a
           bankrupt, or for reorganization, or for arrangement under any
           bankruptcy act;

     (b)   the commencement of any action or proceeding for the dissolution or
           liquidation of Tenant, whether instituted by or against tenant, or
           for the appointment of a receiver or trustee of the property of
           Tenant under any state or federal statute for relief of debtors;

     (c)   the making by Tenant of an assignment for the benefit of creditors;

     (d)   the filing of a tax lien or a mechanics' lien against any property of
           Tenant;

     (e)   Tenant's causing or permitting the Premises to be abandoned for a
           period in excess of ten (10) days;

                                       19


<PAGE>


     (f)   failure by Tenant to pay Landlord when due Basic Rent, Additional
           Rent herein reserved, or any other sum by the time required by the
           terms of this Lease;

     (g)   a failure by Tenant in the performance of any other term, covenant,
           agreement or condition of this Lease on the part of Tenant to be
           performed;

     (h)   a default by Tenant under any other lease or sublease with Landlord.

                                  ARTICLE XVII
                     Landlord's Rights Upon Tenant's Default

      17.1 Upon a Default by Tenant or any subtenant or assignee: (a) Landlord,
upon failure of Tenant to cure a default within ten (10) days of the due date in
the payment of Basic Rent, Additional Rent or any other sum of money due to
Landlord hereunder on the day same was due (without notice thereof from
Landlord) or to cure or diligently commence to cure any other Default within
thirty (30) days after notice thereof from Landlord (provided same is cured
within a reasonable time thereafter and without any delay), may immediately or
at any time thereafter, without further notice to Tenant (i) enter upon the
Premises as agent for Tenant, by legal entry, without terminating this Lease and
do any and all acts as Landlord may deem necessary, proper or convenient to
curing such Default, for the account of and at the expense of Tenant, and Tenant
agrees to pay Landlord, upon demand, all damages and/or expenses incurred by
Landlord in so doing: or (ii) terminate this Lease and Tenant's right to
possession of the Premises and, with or without legal process, take possession
of the Premises and remove Tenant, any occupant and any property therefrom,
using such legal means, without being guilty of trespass and without
relinquishing any rights of Landlord against Tenant.

      (b) Landlord shall be entitled to recover damages foam Tenant in an amount
equal to the amount herein covenanted to be paid as Basic Rent and Additional
Rent, together with: (i) all expenses of any proceedings (including but not
limited to, Legal expenses and attorney's fees) which may be necessary in order
for Landlord to recover possession of the Premises: and (ii) the expenses of
re-renting the Premises including, but not limited to, any commissions paid to
any real estate broker, advertising expenses and the costs of such alterations,
repairs, replacements and decoration or redecoration as Landlord in ins sole
judgement considers advisable and necessary for the purpose or re-renting the
Premises; provided, however, that there shall be credited against the amount of
such damages all amounts received by Landlord from such re-renting of the
Premises. Landlord shall in no event be liable in any way whatsoever for failure
to collect the rent thereof under such re-renting. However, Landlord shall be
under no obligation to re-rent the Premises.

                                       20

<PAGE>


      17.2 No act or thing done by Landlord shall be deemed to be an acceptance
of Tenant's surrender of the Premises, unless Landlord should execute a written
agreement of surrender with Tenant. Tenant's liability hereunder shall not be
terminated by the execution of a new lease of the Premises by Landlord. Tenant
agrees to Pay to Landlord, upon demand, the amount of damages herein provided
after the amount of such damages for any month shall have been ascertained;
provided however, that any expenses incurred by Landlord shall be deemed to be a
part of the damages for the month in which they were incurred. Separate actions
may be maintained each month by Landlord against Tenant to recover the damages
then due, without waiting until the end of the Term to determine the aggregate
amount of such damages or Landlord, at its option, if the Premises have been
re-let for a term extending at least as long as the remainder of the Term
hereof, may hold Tenant in advance for the entire deficiency to be realized
during the term of the re-letting. Tenant hereby expressly waives any and all
rights of redemption granted by or under any present or future laws in the event
of the eviction of Tenant or Tenant being dispossessed for any cause, or in the
event of Landlord obtaining possession of the Premises by reason of the
violation by Tenant of any of the covenants or conditions of this Lease.

      17.3 Landlord may retain, as partial liquidated damages, any Basic Rent,
Additional Rent, Security Deposit or monies received from Tenant or others on
behalf of Tenant.

      17.4 Landlord shall have the right, as agent for Tenant, to take
possession of any furniture or fixtures of tenant found upon the Premises after
taking possession of same pursuant to this Article XVII and sell the same at any
private or public sale and apply the proceeds to any amount due Landlord. Tenant
waives any notice of execution or levy in connection therewith.

                                  ARTICLE XVIII
                    Landlord's Remedies Cumulative: Expenses

      18.1 All rights and remedies of Landlord herein enumerated shall be
cumulative, and none shall exclude any other right or remedy allowed by law. For
the purposes of any suit brought or based herein, this Lease shall be construed
to be a divisible contract, to the end that successive actions may be maintained
on this Lease as successive periodic sums which mature hereunder.

      18.2 Tenant shall pay, upon demand, all of the Landlord's costs, charges
and expenses, including the fees of counsel, agents and others retained by
Landlord, incurred in enforcing Tenant's obligations hereunder.


                                       21

<PAGE>


      18.3 If Tenant fails to pay an installment of Basic Rent, Additional Rent
or any other sum due and payable to Landlord on or before the fifth day of the
calendar month following the date when such installment becomes due and payable,
Tenant shall pay to Landlord a late charge (to cover Landlord's administrative
and overhead expenses of processing late payments) equal to six percent (6%) of
the amount of such installment and, in addition, if the payment is not received
within thirty (30) days of the due date than, such unpaid installment shall bear
interest at the rate per annum which is two percent (2%) greater than the "prime
rate" then in effect (or if such prime rate is not available, a replacement rate
designated by Landlord) from the date such installment became due and payable to
the date of payment thereof by Tenant; provided, however, that nothing herein
contained shall be construed or implemented in such a manner as to allow
Landlord to charge or receive interest in excess of the maximum legal rate then
allowed by law. Such late charge and interest shall constitute Additional Rent
hereunder due and payable with the next monthly installment of Basic Rent.

                                   ARTICLE XIX
                                    No Waiver

      19.1 No waiver by Landlord of any breach by Tenant of any of the terms,
covenants, agreements, or conditions of this Lease shall be deemed to constitute
a waiver of any succeeding breach thereof, or a waiver of any breach of any of
the terms, covenants, agreements and conditions herein contained.

      19.2 No employee of Landlord or of Landlord's representatives or agents
shall have any authority to accept the keys of the Premises prior to the
Expiration date and the delivery of keys to any employees of Landlord or
Landlord's representatives or agents shall not operate as an acceptance of a
termination of this Lease or an acceptance of a surrender of the Premises.

      19.3 The receipt by Landlord of the Basic Rent and Additional Rent with
knowledge of the breach of any covenant of this Lease shall not be deemed a
waiver of such breach. No payment by Tenant or receipt by Landlord of a lesser
amount than the monthly Basic Rent or a lesser amount of the Additional Rent
then due shall be deemed to be other than on account of the earliest stipulated
amount then due, nor shall any endorsement or statement on any check or any
letter or other instrument accompanying any check or payment as Basic rent or
Additional Rent be deemed an accord and satisfaction and Landlord may accept
such check or payment without prejudice to Landlord's right to recover the
balance of such Basic Rent or Additional Rent or pursue any other remedy
provided in this Lease.

                                       22

<PAGE>


      19.4 The failure of Landlord to enforce any of the Rules or Regulations as
may be set by Landlord from time to time against Tenant or against any other
tenant in the Building shall not be deemed a waiver of any such Rule or
Regulation.

                                   ARTICLE XX
                           Landlord's Reserved Rights

      20.1 (a) Landlord reserves the following rights: (i) If during the last
ninety (90) days of the Term, Tenant vacates the Premises, to decorate, remodel,
repair, alter or otherwise prepare the Premises for reoccupancy and, (ii) To
have pass keys to the Premises.

         (b) Landlord may exercise either of the foregoing rights hereby
reserved without being deemed to have caused an eviction or disturbance of
Tenant's use and possession of the Premises and without being liable in any
manner to Tenant.

                                   ARTICLE XXI
                              Landlord's Liability

      21.1 Except for Landlord's gross negligence or willful misconduct,
Landlord or its agents or representatives shall not be liable for any injury or
damage to persons or property resulting from fire, explosion, falling plaster,
steam, gas, electricity, water, rain, snow or leaks from any part of the
Building or from the pipes, appliances, plumbing, or the roof, street,
subsurface or from any other place or by dampness or by any other cause of
nature whatsoever; or resulting from the carelessness, negligence or improper
conduct on the part of any other tenant or of Landlord's contractors or its or
any other tenant's agents, employees, guests, licensees, invitees, subtenant's
assignees or successors.

      21.2 Anything contained in this Lease to the contrary notwithstanding,
Tenant agrees that it shall look solely to the estate and property of Landlord
in the Real Property and the Building of which the Premises form a part for the
collection of any judgement (or other judicial process) requiring the payment of
money by Landlord for any default or breach by Landlord of any of its
obligations under this Lease, subject, however, to the prior rights of any
ground or underlying landlord or the holder of any mortgage covering the Real
Property or the Building or of Landlord's interest therein. No other assets of
Landlord shall be subject to levy, execution or other judicial process for the
satisfaction of Tenant's claim. This provision shall not be deemed, construed or
interpreted to be or constitute an agreement, express or implied, between
Landlord and Tenant that Landlord's interest hereunder and in the Real Property
or the Building shall be subject to impressment of an equitable lien otherwise.
Nothing herein contained shall be construed to limit any right of injunction
against Landlord, where appropriate.

                                       23

<PAGE>


      21.3 Landlord shall not be deemed in default with respect to the failure
to perform any of the terms, covenants and conditions of this Lease on
Landlord's part to be performed, if such failure is due in whole or in part to
any strike, lockout, labor dispute (whether legal or illegal), civil disorder,
inability to procure materials, failure of power, restrictive governmental laws
and regulations, riots, insurrections, war, fuel shortages, accidents,
casualties, Acts of God, acts caused directly or indirectly by Tenant (or
Tenant's agents, employees, guests or invitees), acts of other tenants or
occupants of the Building or any other cause beyond the reasonable control of
Landlord. In such event, the time for performance by Landlord shall be extended
by an amount of time equal to the period of the delay so caused. Landlord shall
use best efforts to restore as quickly as possible.

                                  ARTICLE XXII
                               Tenant's Liability

      22.1 Tenant shall reimburse Landlord for all expenses, damages or fines,
incurred or suffered by Landlord by reason of any breach, violation or
non-performance by Tenant, its agents, servants, employees, invitees or
licensees of any covenant or provision of this Lease, or by reason of damage to
persons or property caused by moving property of or for Tenant in or out of the
Building, or by the installation or removal of furniture or other property of or
for Tenant or by reason of or arising out of the carelessness, negligence or
improper conduct of Tenant, or its agents, servants, employees, invitees and
licensees in the use or occupancy of the Premises. Any such expense shall be
deemed Additional Rent, due in the next calendar month after it is incurred.

                                  ARTICLE XXIII
                               Tenant's Insurance

      23.1 (a) Notwithstanding Article XXII, Tenant covenants to provide on or
before the Commencement Date for the benefit of Landlord, Landlord's mortgagee,
Landlord's Managing Agent and Tenant a comprehensive policy of liability
insurance and/or Certificate of Insurance protecting Landlord, Landlord's
mortgagee, and Landlord's Managing Agent and Tenant against any liability
whatsoever occasioned by accident on the Premises or in the common areas of the
Building, including the parking areas or any appurtenances thereto. Such policy
is to be written by insurance companies qualified to do business in the State of
New Jersey, which shall be rated grade A or better in Best's with a rating
therein of 12 or better and the limits of liability thereunder shall be in at
least the following minimum amounts:

A.    Workmen's Compensation                            Statutory.

                                       24


<PAGE>


B.    Employers Liability                               Not less than $100,000
C.    Broad Form Comprehensive                          Not less than $2,000,000
      General Liability Insurance                       combined single limit
      including Contractual                             for both bodily injury
      Liability, Broad Form                             and property damage
      Property Damage, Personal
      Injury, Completed Operations,
      Products Liability, Fire Damage

Such insurance may be carried under a blanket policy covering the Premises and
other locations of Tenant, if any.

      (b) Fire and Extended Coverage, Vandalism, Malicious Mischief and Special
Extended Coverage Insurance in an amount adequate to cover the cost of
replacement of all personal property, decoration, trade fixtures, furnishings,
equipment in the Premises and all contents therein. Landlord shall not be liable
for any damage to such property of Tenant by fire or other peril includable in
the coverage afforded by the standard form of fire insurance policy with
extended coverage endorsement attached (whether or not such Coverage is in
effect), no matter how caused, it being understood that the Tenant will look
solely to its insurer for reimbursement.

      23.2 Prior to the time such insurance is first required by this Article
XXIII to be carried by Tenant, and thereafter, at least thirty (30) days prior
to the expiration of any such policy, Tenant agrees to deliver to Landlord
either a duplicate original of the aforesaid policy or a certificate evidencing
such insurance, provided said certificate contains an endorsement that such
insurance may not be canceled except upon thirty (30) days' notice to Landlord,
together with evidence of payment for the policy.

      23.3 Upon failure at any time on the part of Tenant to procure and deliver
to Landlord the policy or certificate of insurance, as hereinabove provided,
stamped "Premium Paid" by the issuing company at least thirty (30) days before
the expiration of the prior insurance policy or certificate, if any, or to pay
the premiums therefor, Landlord shall be at liberty, from time to time, as often
as such failure shall occur, to procure such insurance and to pay the premium
therefor, and any sums paid for insurance by Landlord shall be and become, and
are hereby declared, to be Additional Rent hereunder due immediately for the
collection of which Landlord shall have all the remedies provided for in this
Lease or by law for the collection of rent. Payment by Landlord of such premium
or the carrying by Landlord of any such policy shall not be deemed to waive or
release the default of Tenant with respect thereto. Tenant's failure to provide
and keep in force the aforementioned insurance shall be regarded as a Default
hereunder entitling Landlord to exercise any or all of the remedies as provided
in this Lease in the event of Default.


                                       25

<PAGE>


      23.4 Landlord shall maintain fire and extended coverage on the Building
and improvements at the property in amounts reasonably satisfactory to Landlord.

                                  ARTICLE XXIV
                                Mechanics' Liens

      24.1 Any mechanics' liens filed against the Real Property for work claimed
to have been done for, or materials claimed to have been furnished to, Tenant
shall be bonded by Tenant within thirty (30) days after notice of filing at
Tenant's expense.

                                   ARTICLE XXV
                                 Quiet Enjoyment

      25.1 Landlord covenants and agrees that, upon the performance by Tenant of
all of the covenants, agreements and provisions hereof on Tenant's part to be
kept and performed, Tenant shall have, hold and enjoy the Premises, subject and
subordinate to the rights set forth in Article VIII, free from any interference
whatsoever by, from or through Landlord, provided, however, that no diminution
or abatement of Basic Rent, Additional Rent or other payment to Landlord shall
be claimed by or allowed to Tenant for inconvenience or discomfort arising from
the making of any repairs or improvements to the Premises or the Real Property,
nor for any space taken to comply with any law, ordinance or order of any
Governmental Authority, except as provided for herein.

                                  Article XXVI
                              Relocation of Tenant

      26.1 Landlord shall have the right, upon giving to Tenant thirty (30)
days' prior written notice, to relocate Tenant by substituting for the Premises
described herein other space in the Building containing approximately as much
area as that contained in the Premises and by paying Tenant's reasonable moving
and relocation expenses. Such substituted space shall be improved by Landlord,
at its expense, with Tenant finished improvements comparable in quantity and
quality to those made in the Premises. Landlord shall pay all reasonable
expenses incurred by Tenant in connection with such relocation, including the
moving, door lettering and telephone relocation. In connection with such
relocation, Landlord and Tenant shall amend this Lease to change the description
of the Premises and any other matter which may pertain thereto.

                                       26

<PAGE>


                                  ARTICLE XXVII
                               Landlord's Services

      27.1 Landlord shall furnish to Tenant the services set forth in this Lease
and the Rules and Regulations as services which are covered by the Basic Rent.

      27.2 Air heating and air cooling shall be furnished for the common areas
only between the hours of 8:00 a.m. and 6:00 p.m., Mondays through Fridays
(hereinafter referred to as the "Business Hours"), with Saturdays, Sundays and
Building Holidays excluded, and then only when weather conditions, in the
opinion of Landlord, require. As used herein, the term "Building Holidays" shall
mean all holidays including, but not limited to: President's Day, Memorial Day,
Independence Day, Labor Day, Columbus Day, Veteran's Day, Thanksgiving Day and
the day after, Christmas Day and New Year's Day, as each of said holidays are
celebrated in the State of New Jersey.

      27.3 (a) Throughout the Term, Landlord agrees that electrical energy to
the Premises (not exceeding the present electrical capacity at the Premises),
will be provided in the manner specified in Item M of the Basic Lease
Provisions. Landlord shall not be liable in any way to Tenant for any loss,
damage or expense which Tenant may sustain or incur as a result of any failure,
defect or change in the quantity or character of electricity furnished to the
Premises or if such quantity or character of electricity furnished to the
Premises is no longer available or suitable for Tenant's requirements or due to
any cessation, diminution or interruption of the supply thereof. Tenant shall be
responsible for the cost and expense of replacing all light bulbs, fluorescent
bulbs, fluorescent lamps, non-building standard lamps and bulbs, and all
ballasts used by Tenant in the Premises, plus a ten (10%) percent management
fee.

         (b) Tenant covenants that its use of electricity in the Premises shall
be limited to and for the operation of (1) the Building standard lighting, and
(2) personal computers, electric typewriters, calculators, copying machines and
other small office machines.

         (c) Tenant shall make no alteration to the existing electrical and gas
equipment or connect any fixtures, appliances or equipment in addition to the
equipment permitted in Article 21.3(b) above without the prior written consent
of Landlord in each instance. Should landlord grant such consent, all additional
risers or other equipment required therefor shall be provided by Landlord and
the cost thereof shall be paid by Tenant upon Landlord's demand.

         (d) Landlord shall not be liable in the event of any interruption in
the supply of electricity and gas, and Tenant agrees that such supply may be
interrupted for inspection, repairs, replacement and in emergencies.

                                       27

<PAGE>


       27.4 The failure of Landlord to furnish any service hereunder shall not
be construed as a constructive eviction of Tenant and shall not excuse Tenant
from performing any of its obligations hereunder and shall not give Tenant any
claim against Landlord for damages for failure to furnish such service .

                                 ARTICLE XXVIII
                                 Additional Rent

      28.1 Tenant hereby covenants and agrees to pay as additional rent the
amounts as set forth hereinbelow.

      28.2 Tenant's Proportionate Share of the total annual real estate taxes,
assessments, (including special assessment), personal property tax, sewer rents,
rates and charges (hereinafter referred to as the "Real Estate Taxes") which
shall be levied, imposed or assessed upon the Real Property. Taxes are paid
quarterly by the Landlord and appropriate billing will be submitted to the
Tenant quarterly, setting forth the amount of the taxes paid or to be paid, at
which time the Tenant will be required to pay said amount to the Landlord as
additional rent hereunder.

      28.3 During the Term of this Lease, Tenant shall pay to Landlord its
Proportionate Share of the Landlord's Operating Expenses.

      28.4 The "Landlord's Operating Costs" shall be the cost and expense of
operating and maintaining the Building and the Real Property, including the
Common Facilities, in a manner deemed by Landlord to be reasonable and
appropriate and for the best interests of the Entire Premises, including,
without limitation, all reasonable costs and reasonable expenses of operating,
maintaining, managing, repairing, replacement, lighting, cleaning, painting,
stripping, insuring, policing and securing (including the cost of uniforms,
equipment and all employmant taxes), heating, ventilating and air-conditioning
the Common Facilities or the Entire Premises as a whole; each and every expense
incurred in connection with the ownership, administration, management, operation
and maintenance of the Entire Premises, including, but not limited to, wages,
salaries and fees paid to persons either employed by Landlord or engaged as
independent contractors in the operation of the Entire Premises and such other
typical items of expense as indicated below; operating and maintaining any
sprinkler system serving the Entire Premises, as a whole or the Common
Facilities; any electrical, gas, water and sewer costs and charges relating to
the Common Facilities or the Entire Premises as a whole (except to the extent
separately charged to Tenants); taxes, insurance, including liability insurance
for personal injury, death and property damage, flood insurance (if required by
mortgagee), insurance against fire, extended coverage and such other casualty
insurance as Landlord shall deem appropriate, rental


                                       28


<PAGE>


insurance, boiler and machinery insurance, insurance against liability for
defamation (except to the extent separately charged to Tenants); plate glass
insurance for glass exclusively serving the area in which the Common facilities
are from time to time located or the Entire Premises as a whole: cleaning costs,
including, but not limited to, window cleaning, general office cleaning,
cleaning of common areas; service contracts, including but not limited to;
contracts for elevator service, HVAC service, rubbish removal, carting,
janitorial and watchman services and snow removal; costs of landscaping; cost of
insurances fees and/or salaries of superintendents, engineers, custodians; towel
service for common lavatories; removal of snow, ice and debris; regulation of
traffic; costs and expenses of inspection and personal property taxes and other
charges incurred in connection with such equipment; costs and expenses of
replacement of paving, curbs, walkways, landscaping, drainage, pipes, ducts,
conduits, lighting facilities and similar items; costs and expenses of repairing
and other structural repairs relating to the Entire Premises; or if reimbursed
to Landlord within the scope of fire or other casualty insurance coverage; costs
and expense of planting, replanting and replacing flowers, shrubbery and
planters; services, if any, furnished by Landlord for non-exclusive use of all
Lessees on a non-profit basis, including parcel pick-up and delivery services
and shuttle bus services. Provided, however, to the extent that any common areas
such as waiting or reception areas are limited to some but not all Tenants, then
only those Tenants to whom the common facility is limited shall share pro rata
in accordance with the aforementioned formula. Landlord shall, in writing,
designate those limited Common Facilities.

      28.5 The charges required hereunder shall be paid by Tenant in monthly
installments with monthly installments of Annual Basic Rent in such amounts as
are estimated by Landlord, together with such additional amounts and credits
invoiced by Landlord as and when Landlord's Operating Costs for any accounting
year of Landlord have been determined, within thirty (30) days of Landlord's
statement therefor. Upon Tenant's reasonable notice, Landlord shall make
available for Tenant's inspection, during normal business hours, Landlord's
records relating to Landlord's Operating Costs for the period covered by any
invoice. Failure of Landlord to provide the statement called for hereunder,
within the time prescribed, shall not discharge Tenant from its obligation
hereunder. In the event of any overpayment, such overpayment shall be refunded
to Tenant. In the event Landlord or any mortgagee should require any particular
Operating Cost to be escrowed, such escrow items shall be paid by Tenant.

                                  ARTICLE XXIX
                             Personal Property Taxes

      29.1 Tenant agrees to pay all taxes imposed on the personal property of
Tenant, the conduct of its business and its use and occupancy of the Premises.


                                       29

<PAGE>


                                   ARTICLE XXX
                                Security Deposit

      30.1 Simultaneously with the execution hereof, Tenant has deposited with
Landlord the sum as specified in Item F of the Basic Lease Provisions.

                                  ARTICLE XXXI
                             Use of Security Deposit

      31.1 In the event of a Default by Tenant in respect of any of the terms,
covenants or conditions of this Lease, Landlord may use, apply or retain the
whole or any part of the Security Deposit to the extent required for the payment
of any Basic Rent, Additional Rent or any other sum as to which Tenant is in
Default or for any sum which Landlord may expend or may be required to expand by
reason of Tenant's Default in respect of any of the terms, covenants or
conditions of this Lease, including but not limited to, any damages or
deficiency accrued before or after summary proceedings or other re-entry by
Landlord. In the event that Tenant shall fully and faithfully comply with all of
the terms, covenants and conditions of this Lease, the Security Deposit shall be
returned to Tenant within thirty (30) days after the Expiration Date and after
delivery of possession of the Premises to Landlord. For all purposes hereunder,
the security deposit shall be deemed additional rent.

      31.2 In the event of a sale of the Real Property or a leasing thereof,
Landlord shall have the right to transfer the Security Deposit to the vendee or
Tenant, as the case may be, and Landlord shall thereupon be released by Tenant
from all liability for the return of such Security Deposits and Tenant agrees to
look to the new landlord solely for the return of the Security Deposit; and it
is agreed that the provisions hereof shall apply to every transfer or assignment
made of the Security Deposit to a new landlord. Tenant further covenants that it
will not assign or encumber or attempt to assign or encumber the Security
Deposit and that neither Landlord nor its successors or assigns shall be bound
by any such assignment, encumbrance, attempted assignment or attempted
encumbrance.

                                  ARTXCLE XXXII
                             Definition of Landlord

      32.1 The Term "Landlord" as used in this Lease means only the owner for
the time being of the Real Property and/or the Building or the owner of a lease
of the Real Property. In the event of any transfer of title to or lease of the
Real Property, Landlord

                                       30

<PAGE>


shall be and hereby is entirely freed and relieved of all covenants and
obligations of Landlord hereunder and this Lease shall be deemed and construed
as a covenant running with the land without further agreement between the
parties or their successors in interest.

      32.2 Landlord shall be under no personal liability with respect to any of
the provisions of this Lease, and if Landlord is in breach or default with
respect to its obligations or otherwise, Tenant shall look solely to the equity
of Landlord in Real Property for the satisfaction of Tenant's remedies. It is
expressly understood and agreed that Landlord's liability under the terms,
covenants, conditions, and obligations of this Lease shall in no event exceed
the loss of its equity in the Real Property.

                                 ARTICLE XXXIII
                                     Notices

      33.1 Notices by either party to the other shall be in writing, sent via
registered or certified mail, return receipt requested, postage prepaid and
addressed to Landlord or Tenant at their respective addresses as specified in
Items H(1) and H(2) of the Basic Lease Provisions, or to such other address as
either party shall hereafter designate by notice as aforesaid. All notices
properly addressed shall be deemed served three (3) business days after the date
of mailing.

                                  ARTICLE XXXIV
                                      Signs

      34.1 No sign advertisement or notice shall be affixed to or placed upon
any part of the Premises, the Building or the Real Property by the Tenant,
except Tenant's entry door and the directory in the respective lobby. The size,
design and color shall be as approved in advance in writing by Landlord, which
approval shall not be unreasonably withheld or delayed.

                                  ARTICLE XXXV
                         Notice of Defects and Accidents

      35.1 Tenant shall give Landlord prompt notice in case of accident on the
Premises involving Tenant, its servants, agents, employees, invitees or
licensees in the Building or on the Real Property or of any defects in the
Building.

                                       31

<PAGE>


                                  ARTICLE XXXVI
                              Rules and Regulations

      36.1 Tenant, on behalf of itself and its employees, agents, servants,
invitees and licensees, agrees to comply with the Rules and Regulations attached
hereto and incorporated by reference as Exhibit C with respect to the Real
Property. Landlord shall have the right to make reasonable amendments thereto
from time to time for the safety, care and cleanliness of the Real Property and
the Building, the preservation of good order therein and the general convenience
of all the tenants and Tenant agrees to comply with such amended Rules and
Regulations, after twenty (20) days' written notice thereof from Landlord.

                                 ARTICLE XXXVII
                                    Directory

      37.1 Landlord shall furnish and service in the lobby of the Building a
tenant directory. Tenant, at its expense, may request from Landlord and pay for
such reasonable and customary number of names that Tenant may from time to time
request to be listed in such directory.

                                 ARTICLE XXXVIII
           Hazardous Materials and Compliance with Environmental Laws

      38.1 Tenant shall not cause or permit any hazardous or toxic substance,
except as otherwise provided in this paragraph, material or waste which is or
becomes regulated by any local governmental authority, of the United States
Government ("Hazardous Material") to be brought upon, kept, or used in or about
the Premises by Tenant, its agents, employees, contractors or invitees, without
the prior written consent of Landlord (which demonstrates to Landlord's
reasonable satisfaction that such Hazardous Material is necessary or useful to
Tenant's business and will be used, kept in or about the Premises). If Tenant
breaches the obligations stated in the preceding sentence, or if the presence of
Hazardous Material on the Premises, the Building or the Real Property caused or
permitted by Tenant results in contamination of the Premises, the Building, or
the Real Property by Hazardous Material or otherwise occurs, for which Tenant is
legally liable to Landlord for damage resulting therefrom, then Tenant shall
indemnify, defend and hold Landlord harmless from any and all claims, judgments,
damages, penalties, fines, costs, liabilities or losses (including, without
limitation, diminution in value of the Premises, the Building, or the Real
Property, damages for the loss or restriction on use of rentable or usable space
or of any amenity of the Premises, the Building, or the Real Property, damages
arising from any adverse impact on marketing of space, and sums paid in
settlement of claims, attorney's fees,

                                       32


<PAGE>


consultant fees and expert fees] which arise during or after the Term as a
result of such contamination. This indemnification of Landlord by Tenant
includes, without limitation, costs incurred in connection with any
investigation of site conditions or any cleanup, remedial, removal, or
restoration work required by any federal, state or local governmental agency or
political subdivision because of Hazardous Material present including in the
soil or ground water on or under the Building. Without limiting the foregoing,
if the presence of any Hazardous Material on the Premises, the Building, or the
Real Property, caused or permitted by Tenant results in any contamination of the
Premises, the Building, or the Real Property, Tenant shall promptly take all
actions at its sole expense as are necessary to return the Premises and/or the
Building, and/or the Real Property to the condition existing prior to the
introduction of any such Hazardous Material to the Premises and/or the Building
and/or the Real Property; provided that Landlord's approval of such actions
shall first be obtained, which approval shall not be unreasonably withheld so
long as such actions would not potentially have any material adverse long-term
or short-term effect on the Premises, the Building or the Real Property.
Notwithstanding anything to the contrary provided herein, Landlord's approval
shall not be required for the lawful storage of materials regularly used in the
ordinary course of Tenant's business; provided, however, upon request of the
Landlord, Tenant shall provide Landlord with a list of materials being stored.

      38.2 Tenant shall, at Tenant's sole cost and expense, comply with the
requirements of any Federal, state, county, municipal or other governmental law,
ordinance, rule, regulation, requirement and/or directive pertaining to the
environment (an "Environmental Law" or "Environmental Laws") including, but not
limited to, the New Jersey Spill Compensation and Control Act (N.J.S.A.
58:10-23.11 ET SEQ.); the New Jersey Water Pollution Control Act (N.J.S.A. 58:
10A-1 ET SEQ.); the Worker and Community Right to Know Act (N.J.S.A. 34:5A-1 ET
SEQ.); the Resource Conservation and Recovery Act of 1976 (42 U.S.C. Section
6901 ET SEQ.); the comprehensive Environmental Response Compensation and
Liability Act of 1980 (42 U.S.C- Section 9601 ET SEQ.); and the industrial Site
Recovery Act and the regulations promulgated thereunder ("ISRA"). ln this
regard, Tenant shall, at Tenant's sole cost and expense, make all submissions
to, provide all information to and comply with all requirements of any
governmental authority. Should said governmental authority determine that action
is necessary to clean up, remove and/or eliminate any spills or discharges by
Tenant or dangerous or hazardous substances or wastes in and upon the Premises,
the Building and/or the Real Property caused by Tenant or its agents, servants,
employees, licensees, invitees and contractors and/or that a cleanup plan must
be prepared and submitted, then and in that event, Tenant shall, at Tenant's
sole cost and expense, take any and all action required and carry out any and
all approved plans. Tenant's obligations pursuant to this section shall arise
whenever required by any appropriate governmental agency, including, but not
limited to, any closing, terminating or transferring of operations at the
Premises.

                                       33

<PAGE>


      38.3 Tenant shall, at Tenant's sole cost and expense, comply with ISRA.
Tenant shall, at Tenant's sole cost and expense, make all submissions to,
provide any information to, and comply with all requirements of, the Bureau of
Industrial Site Evaluation ("the Bureau") of the New Jersey Department of
Environmental Protection ("NJDEP") applicable to its use of the Premises. Should
the Bureau or any other division of NJDEP determine that a cleanup plan be
prepared and that a cleanup be undertaken because of any spills or discharges of
hazardous substances or wastes at the Premises caused by Tenant or its agents,
servants, employees, licensees, invitees and contractors which occur during the
Term or any renewal thereof, as the case may be, then Tenant shall, at Tenant's
sole cost and expense, prepare and submit the required plans and financial
assurances, and carry out the approved plans. Tenant's obligations under this
Article XXXVIII shall also arise if there is any closing, terminating or
transferring of Tenant's operations at the Premises subject to ISRA, including
without limitation, a sale, transfer or conveyance of the Premises by Tenant, an
assignment or subletting by Tenant, or the vacation of the Premises by Tenant
for any reason whatsoever. At no expense to Landlord, Tenant shall promptly
provide all information within its personal knowledge requested by Landlord for
preparation of non-applicability affidavits and shall promptly sign such
affidavits when requested by Landlord. Tenant shall indemnify, defend and hold
harmless Landlord from all fines, suits, procedures, claims and actions of any
kind arising out of or in any way connected with any spills or discharges of
hazardous substances or wastes at the Premises which occur during the Term or
any renewal thereof, as the case may be and which are caused by Tenant or its
agents, servants, employees, licensees, invitees and contractors; and from all
fines, suits, procedures, claims and actions of any kind arising out of tenant's
failure to provide all information, make all submissions and take all actions
required by the ISRA Bureau or any other division of NJDSP. Tenant's failure to
abide by the terms of this Article XXXVIII shall be enforceable in a court of
law and subject to all equitable remedies. Tenant's obligations hereunder shall
survive the Expiration Date of this Lease.

                                  ARTICLE XXXIX
                                  Miscellaneous

      39.1 ENTIRE AGREEMENT. This Lease contains the entire agreement between
the parties, and any attempt hereafter made to change, modify, discharge or
effect an abandonment of it in whole or in part shall be void and ineffective
unless in writing and signed by the party against whom enforcement of the
change, modification, discharge or abandonment is sought.

      39.2 JURY TRIAL WAIVER. Landlord and Tenant do hereby waive trial by jury
in action, proceeding or counterclaim brought by either of the parties hereto
against the other on any matter arising out of or in any connection with this
Lease, the relationship

                                       34

<PAGE>


of Landlord and Tenant, Tenant's use or occupancy of the Premises, and/or any
claim, injury or damage, or any emergency or statutory remedy.

      39.3 FORCE MAJEURE. If, by reason of strike, labor troubles or other cause
beyond Landlord's control, including, but not limited to, governmental
preemption in connection with a national emergency or any rule, order or
regulation of any Governmental Authority, or conditions of supply and demand
which are affected by war or other emergency, Landlord shall be unable to
fulfill its obligations under this Lease or shall be unable to supply any
service which Landlord is obligated to supply, this Lease and Tenant's
obligation to pay Basic Rent and Additional Rent hereunder shall except as
otherwise provided herein, in no way be affected, impaired or excused.

      39.4 BROKER. Landlord and Tenant represents that they have not dealt with
any real estate brokers in connection with this Lease, other than as specified
in Item G of the Basic Lease Provisions. Landlord and Tenant indemnify and hold
each other harmless of and from any and all claims, liabilities, costs or
damages Landlord may incur as a result of a breach of this representation.

      39.5 SEPARABILITY. If any term or provision of this Lease or the
application thereof to any person or circumstance shall, to any extent, be
invalid or unenforceable, the remainder of this Lease, or the application of
such term or provision to persons or circumstances other than those to which it
is held invalid or unenforceable, shall not be effected thereby and all other
terms and provisions of this Lease shall be valid and enforced to the fullest
extend permitted by law.

      39.6 (a) INTERPRETATION. Whenever in this Lease any words of obligation or
duty are used, such words or expressions shall have the same force and effect as
though made in the form of covenants.

      (b) Words of any gender used in this Lease shall be held to include any
other gender, and words in the singular number shall be held to include the
plural, when the sense requires.

      (c) All pronouns and any variations thereof shall be deemed to refer to
the neuter, masculine, feminine, singular or plural as the identity of Tenant
requires.

      (d) This Lease shall be strictly construed neither against Landlord nor
Tenant. No remedy or election given by any provision in this Lease shall be
deemed exclusive unless so indicated, but each shall, wherever possible, be
cumulative with all other remedies in law or equity as otherwise specifically
provided. Each provision hereof shall be deemed both a covenant and a condition
and shall run with the land.

                                       35

<PAGE>


      (e) If, and to the extent that, any of the provisions of any rider,
addendum or amendment to this Lease conflict or are otherwise inconsistent with
any of the preceding provisions of this Lease, or of the Rules and Regulations
appended to this Lease, whether or not such inconsistency is expressly noted in
the rider, addendum or amendment, the provisions of the rider, addendum or
amendment shall prevail, and in case of inconsistency with said Rules and
Regulations, shall be deemed a waiver of such Rules and Regulations with respect
to Tenant to the extent of such inconsistency.

      (f) Tenant agrees that all of Tenant's covenants and agreements herein
contained providing for the payment of money and Tenant's covenant to remove
mechanics' liens shall be deemed conditions as well as covenants, and that if
default be made in any such covenants, Landlord shall have all of the rights
provided for herein.

      (g) The parties mutually agree that the headings and captions contained in
this Lease are inserted for convenience of reference only, and are not to be
deemed part of or to be used in construing this Lease.

      (h) The covenants and agreements herein contained shall, subject to the
provisions of this Lease, bind and inure to the benefit of Landlord, its
successors and assigns, Tenant, its successors and assigns except as otherwise
provided herein.

      (i) This Lease shall be construed in accordance with the laws of the State
of New Jersey, and Landlord and Tenant acknowledge that all of the applicable
statutes of the State of New Jersey are superimposed on the rights, duties and
obligations of Landlord and Tenant hereunder and this Lease shall not otherwise
provide that which said statutes prohibit.

      (j) Landlord has made no representations or provisos with respect to the
Premises or the Real property, except as expressly contained herein. Tenant has
inspected the Premises and agrees to take the same in an "as is" condition,
except as otherwise expressly set forth in Exhibit B, attached hereto and
incorporated by reference herein. Landlord shall have no obligation, except as
set forth in Exhibit B, to do any work in and to the Premises to render the
Premises ready for occupancy and use by Tenant.

      39.7 NO RECORDATION. Tenant shall not record this Lease or a memorandum
hereof.

      39.8 NO PARTNERSHIP. Nothing contained in this Lease shall be deemed or
construed to create a partnership or joint venture of or between Landlord and
Tenant, or to create any other relationship between the parties hereto other
than that of landlord and tenant.

      39.9 AUTHORITY. Landlord and Tenant hereby covenant each for itself, that
each has full right, power and authority to enter into this Lease upon the terms
and conditions

                                       36

<PAGE>


set forth. If Tenant signs as a corporation, each of the persons executing this
Lease on behalf of Tenant does hereby covenant and warrant that Tenant is a duly
authorized and existing corporation, qualified to do business in the
jurisdiction in which the Building is located, that the corporation has full
right and authority to enter this Lease, and that each of the persons signing on
behalf of the corporation was authorized to do so.

      39.10 EXAMINATION OF LEASE. Submission of this Lease to Tenant to
examination or signature by Tenant shall not constitute reservation of or option
to lease, and the same shall not be effective as a lease or otherwise until
execution and delivery by both Landlord and Tenant.

                                       37

<PAGE>


         IN WITNESS WHEREOF, Landlord and Tenant have executed this Lease under
seal on the day and year first hereinabove written.

WITNESS OR ATTEST:                       LANDLORD:
                                             RAD Data Communications,  Inc.

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

WITNESS OR ATTEST:                       TENANT:
                                              RADVISION,  Inc.

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



                                       38

<PAGE>


                         CORPORATE TENANT ACKNOWLEDGMENT

STATE OF NEW JERSEY

                         SS.______________________

COUNTY OF BERGEN

On this ______, day of ______, 19___, before me personally came _________, to me
known, who, being by me duly sworn, did depose and say that she/he resides in
_______ City of__________ State of__________ that she/he is the__________ of
____________, the corporation ______________________________ described in and
which executed the foregoing Lease, as Tenant; that she/he knows the seal of
said corporation; that the seal affixed to said instrument is such corporate
seal; that it was so affixed by order of the Board of Directors of said
corporation, and that she/he signed her/his name thereto by like order.


                                        Notary Public


                        PARTNERSHIP TENANT ACKNOWLEDGMENT

STATE OF

                         SS.____________________

COUNTY OF

         On this _____day of _________19____, before me personally came _______,
to me known, and known to me to be the individuals described in and who executed
the foregoing Lease, as Tenant, and to me acknowledged that each is a partner in
the firm of and that they each executed the same individually and as co-partners
of said firm.


                                        Notary Public


                                       39

<PAGE>


                        INDIVIDUAL TENANT ACKNOWLEDGMENT

STATE OF

                         SS.

COUNTY OF

         On this day of ____, 19__, before me personally came ________ to me
known, and known to me to be the individual described in and who executed the
foregoing Lease, as Tenant, and she/he duly acknowledged to me that she/he
executed the same.


                                           Notary Public




                                       40


<PAGE>


                                    EXHIBIT A

                                  THE PREMISES





                              [Diagram of Premises]






                                       41

<PAGE>


                                    EXHIBIT B

                         LANDLORD'S WORK IN THE PREMISES





                              [Diagram of premises]










                                       42


<PAGE>


                                    EXHIBIT C

                              RULES AND REGULATIONS

         1. Tenant shall not (a) obstruct or permit its employees, agents,
servants, invitees or licensees to obstruct, in any way, the sidewalks, entry
passages, corridors, exit doorways, halls, stairways or elevators of the
Building, or use the same in any way other than as a means of passage to and
from the offices of Tenant; (b) bring in, store, test or use any materials in
the Building which could cause a fire or an explosion or produce any fumes or
vapor; (c) make or permit any improper noises in the Building; (d) smoke in any
elevator; throw substances of any kind out of windows or doors, or down the
passages of the Building, or in the halls t or passageways, sit on or place
anything upon the window sills; or (e) clean the windows.

         2. Water closets and urinals shall not be used for any purpose other
than those for which they were constructed, and no sweepings, rubbish, ashes,
newspaper or any other substances of any kind shall be thrown into them. Waste
and excessive or unusual use of electricity or water is prohibited.

         3. The windows, doors, partitions and lights that reflect or admit
light into the halls or other places of the Building shall not be obstructed. NO
SIGNS, ADVERTISEMENT OR NOTICES SHALL BE INSCRIBED, PAINTED, AFFIXED OR
DISPLAYED IN, ON, UPON, OR BEHIND ANY WINDOWS.

         4. No contract of any kind with any supplier of towels, water, ice,
toilet articles, waxing, rug shampooing, Venetian blind washing, furniture
polishing, lamp servicing, cleaning or repair of electrical fixtures, removal of
waste paper, rubbish or garbage, or other like service shall be entered into by
Tenant, nor shall any vending machine of any kind be installed in the Building
without the prior written consent of Landlord.

         5. Tenant shall not employ any person or persons for the purpose of
cleaning the Premises, without the prior written consent of Landlord and
obtaining a Certificate of Insurance protecting Landlord and Landlord's Managing
Agent, which shall not be unreasonably withheld or delayed, Landlord shall not
be responsible to Tenant for any loss of property from the Premises however
occurring, or for any damage done to the effects of Tenant by janitors or any of
its employees, or by any other person or any other cause.

         6. When electric wiring of any kind is introduced, it must be connected
as directed by Landlord, and no stringing or cutting of wires will be allowed,
except with the prior written consent of Landlord, and shall be done only by
contractors approved by Landlord. The number and location of telephones,
telegraph instruments, electric appliances, call boxes, etc., shall be approved
by Landlord. No tenant shall lay floor


                                       43

<PAGE>


covering so that the same shall be in direct contact with the floor of the
Premises; and if floor covering is desired to be used, an interlining of
builder's deadening felt shall be first affixed to the floor by a paste or other
material, the use of cement or other similar adhesive material being expressly
prohibited.

         7. Tenant must submit to Landlord in writing a description of the
weight, size and position of all safes and other bulky or heavy equipment and
all freight which Tenant proposes to bring into the Building; and including the
time of moving the same in and out of the Building. Tenant shall not bring such
items into the Building until receiving Landlord's written consent. Once such
Landlord consent is received, all such moving shall be done under the strict
supervision of Landlord or Landlord' s property manager. Landlord will not be
responsible for loss or damage to any such equipment or freight from any cause;
but all damage done to the Building by moving or maintaining any such equipment
or freight shall be repaired at the expense of Tenant. All safes shall stand on
a base of such size as shall be designated by Landlord. Landlord reserves the
right to inspect all freight to be brought into the Building and to exclude from
the Building all freight which violates any of these Rules and Regulations of
the Lease of which these Rules and Regulations are a part.

         8. No machinery of any kind or articles of unusual weight or size will
be allowed in the Building, without the prior written consent of Landlord.
Business machines and mechanical equipment shall be placed and maintained by
Tenant at Tenant's expense, in settings sufficient (including proper floor
load), in Landlord's judgement, to absorb and prevent vibration, noise and
annoyance to other tenants.

         9. No additional lock or locks shall be placed by Tenant on any door in
the Building, without the prior written consent of Landlord. Two keys will
initially be furnished to Tenant by Landlord; two additional keys will be
supplied to Tenant by Landlord, upon request, without charge; any additional
keys requested by Tenant shall be paid for by Tenant. Tenant, its agents and
employees, shall not have any duplicate key made and shall not change any lock.
All keys to doors and washrooms shall be returned to Landlord on or before the
Expiration Date or earlier termination of this Lease, and, in the event of a
loss of any keys furnished, Tenant shall pay Landlord the cost thereof.

         10. No bicycles, vehicles (except wheelchairs) or animals of any kind
shall be brought into or kept in or about the Premises.

         11. The requirements of Tenant will be attended to only upon
application at the office of Landlord or Landlord's property manager. Employees
of Landlord or Landlord's property manager shall not perform any work for Tenant
or do anything outside of their regular duties, unless under special
instructions from Landlord.


                                       44

<PAGE>


         12. The Premises shall not be used for lodging or sleeping purposes,
and cooking therein is prohibited.

         13. Tenant shall not conduct, or permit any other person to conduct,
any auction upon the Premises; manufacture or store goods, wares or merchandise
upon the Premises, without the prior written approval of Landlord, except the
storage of usual supplies and inventory to be used by Tenant in the conduct of
its business; permit the Premises to be used for gambling; make any unusual
noises in the Building; permit to be played any musical instrument in the
Premises; permit to be played any radio, television, recorded or wired music in
such a loud manner as to disturb or annoy other tenants; or permit any unusual
odors to be produced upon the Premises.

         14. Tenant will be entitled to access to the Building by master key
during non-business or overtime hours; it shall be Tenant's responsibility to
secure the Premises at the nonbusiness hours when Tenant enters or leaves the
Building.

         15. No awnings or other projections shall be attached to the outside
walls of the Building. No curtains, shades or screens shall be attached to or
hung in, or used in connection with, any window or door of the Premises, without
the prior written consent of Landlord. All blinds must be of a quality, type,
design, and color, and attached in a manner approved by Landlord.

         16. Canvassing, soliciting and peddling on the Real Property or in the
Building are prohibited, and Tenant shall cooperate to prevent the same.

         17. There shall not be used in the Premises or in the Building either
by Tenant or by others in the delivery or receipt of merchandise, supplies or
equipment, any hand trucks except those equipped with rubber tires and side
guards.

         18. Each tenant, before closing and leaving the Premises, shall ensure
that all windows are closed and all entrance doors closed and locked.

         19. No animals of any kind shall be allowed in the Building except for
lead dogs.

         20. Landlord shall have the right to prohibit any advertising by Tenant
which in Landlord's opinion tends to impair the reputation of the Building or
its desirability for offices, and upon written notice from Landlord, Tenant
shall refrain from or discontinue such advertising.

         21. Landlord hereby reserves to itself any and all rights not granted
to Tenant hereunder, including, but not limited to, the following rights which
are reserved for Landlord's purposes in operating the Building: (a) the
exclusive right to the use of the


                                       45

<PAGE>


name of the Building for all purposes, for Landlord or anyone Landlord might
designate, except that Tenant may use the name as its business address and for
no other purpose; (b) the right to change the name or address of the Building,
without incurring any liability to Tenant for so doing; (c) the right to install
and maintain a sign or signs on the exterior of the Building; (d) the exclusive
right to use or dispose of the use of the roof of the Building; (e) the right to
limit the space on the directory of the Building allotted to Tenant; (f) the
right to grant to anyone the right to conduct any particular business or
undertaking in the Building.

         22. Tenant shall have the non-exclusive right to use in common with
Landlord and other tenants of the Building and their employees and invitees the
unassigned parking areas provided by Landlord for the parking of passenger
automobiles. Landlord may issue parking permits, install a gate system, and
impose any other system as Landlord deems necessary for the use of the parking
area. Tenant agrees that it and its employees and invitees shall not park their
automobiles in parking spaces allocated to others by Landlord and shall comply
with such rules and regulations for use of the perking area as Landlord may from
time to time prescribe. Landlord shall not be responsible for any damage to or
theft of any vehicle in the parking area and shall not be required to keep
parking spaces clear of unauthorized vehicles or to otherwise supervise the use
of the parking area. Landlord reserves the right to change any existing or
future parking area, roads or driveways, and may make any repairs or alterations
it deems necessary to the parking area, roads and driveways end to temporarily
revoke or modify the parking rights granted to Tenant hereunder. The persistent
or frequent violation of this right by Tenant, its employees and invitees, which
continues after written notice from the Landlord shall be deemed a default by
Tenant under the terms of this Lease and shall also subject Tenant to a
revocation by Landlord of Tenant's right to use any parking spaces.

         23. Tenant shall not use the Premises or permit the Premises to be used
for the sale of food or beverages.

         24. Tenant, its employees and agents, hereby agree to abide by
reasonable rules and regulations of which Tenant shall be notified in writing
pertaining to the use of the Building as may be hereafter promulgated from time
to time by Landlord.


                                       46

<PAGE>


May 12, 1997

RADVision, Inc.
575 Corporate Drive
Mahwah, NJ 07430

RE:    575 Corporate Drive
       Mahwah, NJ 07430


Dear Sirs:

As of this date, RAD Data Communications, Inc. ("Landlord") and RADVision, Inc.
("Tenant") have entered into a Lease Agreement, relating to space in the
premises known as 575 Corporate Drive, Mahwah, New Jersey, (the "Property").
Notwithstanding the specific terms of said Lease Agreement, as a further
consideration for each of us entering into said Lease Agreement, it is agreed
that for such period of time as Landlord owns the premises, the basic rent
payable by Tenant shall be $8.50 per square foot per annum. In the event at any
time the Property should be sold by Landlord, it is agreed that the basic rent
shall revert to the rental set forth in the Lease Agreement, which is initially
$10.00 per square foot.

Please indicate your acceptance of the above by signing this letter agreement in
the space indicated.

Very truly yours,

/s/PAUL L. SWEENEY
Paul L. Sweeney
Controller
RAD Data Communications, Inc.

Agreed to and accepted this 30th day of May, 1997.

RADVision, Inc.


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

<PAGE>


                          SECOND MODIFICATION OF LEASE

THIS AGREEMENT, made this 16th day of March, 1998, by and between RAD DATA
COMMUNICATIONS, INC., as Landlord, and RADVISION, INC., as Tenant.

                                   WITNESSETH:

        WHEREAS, the Landlord and Tenant heretofore entered into a Lease
Agreement on May 12, 1997, covering approximately 2,148 square feet of office
space in Lobby 4 of the premises located at 575 Corporate Drive, Mahwah, New
Jersey (the "Lease Agreement"); and

        WHEREAS, the Landlord and Tenant heretofore entered in a Modification of
Lease dated September 10, 1997 (the "Modification of Lease"), by which Tenant
agreed to lease an additional 688.5 square feet in the Building (as defined in
the Lease Agreement) on the terms and conditions set forth therein; and

        WHEREAS, the term of the Lease Agreement commenced on May 12, 1997 and
will expire on May 11, 2002; and

        WHEREAS, the parties desire that Tenant shall rent from Landlord an
additional 506 square feet in the Building (as defined in the Lease Agreement),
which space is adjacent to the Premises (as defined in the Lease Agreement),
under the terms and conditions hereinafter set forth.

        NOW, THEREFORE, the parties hereto agree as follows:

       1.    All defined terms in the Lease Agreement shall have the same
             meaning in this Modification of Lease as though set forth herein in
             full.

       2.    The Premises shall be amended to consist of approximately 3,342.5
             rentable square feet, as shown on the Floor Plan attached to this
             Second Modification of Lease as Exhibit "A".

       3.    The Annual Base Rent shall be $33,425.00 Net, which shall be made
             in Monthly Installments of Base Rent of $2,785.42 Net plus Tenant
             Utilities and other pass throughs as set forth in the Lease
             Agreement.

       4.    Tenant's Proportionate Share, as set forth in paragraph E of the
             Lease Agreement, shall be amended to be 2.312%.

       5.    The number of parking spaces set forth in paragraph "L" of the
             Lease Agreement shall be amended to be Fourteen (14) Parking
             Spaces.

<PAGE>


       6.    The percentage as set forth in paragraph "M" of the Lease Agreement
             shall be amended to read 2.312% in all places.

       7.    The per annum figure for Tenant Electric and Gas set forth in
             paragraph "M" of the Lease Agreement shall be amended to be
             $4,178.13.

       8.    The Effective Date of all changes set forth in this Second
             Modification of Lease shall be as of March 16, 1998. The Expiration
             Date of May 11, 2002 set forth in the Lease Agreement shall remain
             unchanged.

       9.    Except for the foregoing terms, conditions and amendments, this
             Second Modification of Lease shall be on the same terms, covenants
             and provisions of the Lease Agreement and the Modification of Lease
             which are now in effect and which are incorporated herein by
             reference thereof as if set forth herein at length.


       IN WITNESS WHEREOF, said parties have hereunto set their hands and seals
this 16th day of March, 1998.


WITNESS:                                  RAD DATA Communications, Inc.
                                            Landlord


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

WITNESS:                                  RADVISION, Inc.
                                               Tenant


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


                                       2

<PAGE>


March 16, 1998


RADVision, Inc.
575 Corporate Drive
Mahwah, NJ 07430

RE:    575 Corporate Drive
       Mahwah, NJ 07430

Dear Sirs:

As of this date, RAD Data Communications, Inc. ("Landlord") and
RADVision, Inc. ("Tenant") have entered into a Second Lease
Modification, relating to space in the premises known as 575 Corporate
Drive, Mahwah, New Jersey, (the "Property"). Notwithstanding the
specific terms of said Lease Modification, as a further consideration
for each of us entering into said Lease Modification, it is agreed that
for such period of time as Landlord owns the premises, the basic rent
payable by Tenant shall be $8.50 per square foot per annum
($28,411.25/year, $2,367.61/month) plus an additional monthly charge of
$180.46 which commenced on November 16, 1997. The latter charge
represents the $9,925 cost of renovations amortized over the remaining
55 months of the lease. In the event at any time the Property should be
sold by Landlord, it is agreed that the basic rent shall revert to the
rental set forth in the Lease Modification, which is initially $10.00
per square foot.

Please indicate your acceptance of the above by signing this letter
agreement in the space indicated.

Very truly yours,


Controller
RAD Data Communications, Inc.

Agreed to and accepted this 16th day of March, 1998.

RADVision, Inc.


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

                                       3


<PAGE>


                           THIRD MODIFICATION OF LEASE

THIS AGREEMENT, made this 25th day of January, 1999, by and between RAD DATA
COMMUNICATIONS, INC., as Landlord, and RADVISION, INC., as Tenant.

                                   WITNESSETH:

         WHEREAS, the Landlord and Tenant heretofore entered into a Lease
Agreement on May 12, 1997, covering approximately 2,148 square feet of office
space in Lobby 4 of the premises located at 575 Corporate Drive, Mahwah, New
Jersey (the "Lease Agreement"); and

         WHEREAS, the Landlord and Tenant heretofore entered into a Modification
of Lease dated September 10, 1997, (the "Modification of Lease"), by which
Tenant agreed to lease an additional 688.5 square feet in the Building (as
defined in the Lease Agreement) on the terms and conditions set forth therein;
and

         WHEREAS, the Landlord and Tenant heretofore entered into a Second
Modification of Lease dated March 16, 1998, (the "Second Modification of
Lease"), by which Tenant agreed to lease an additional 506 square feet in the
Building (as defined in the Lease Agreement) on the terms and conditions set
forth therein; and

         WHEREAS,  the term of the Lease  Agreement  commenced on May 12, 1997
and will expire on May 11, 2002; and

         WHEREAS, the parties desire that Tenant shall be released from renting
the 506 square feet in the Building covered by the Second Modification of Lease
and desire that Tenant shall rent from Landlord an additional 5,630 square feet
in the Building, which space is adjacent to the Premises (as defined in the
Lease Agreement), under the terms and conditions hereinafter set forth.

         NOW, THEREFORE, the parties hereto agree as follows:

         1.       All defined terms in the Lease Agreement shall have the same
                  meaning in this Third Modification of Lease as though set
                  forth herein in full.

         2.       All of the terms and conditions of the Second Modification of
                  Lease relating to the additional 506 square feet in the
                  Building referred to therein are hereby deemed terminated and
                  of no further force and effect. The parties understand that
                  the Tenant will no longer be renting from Landlord the said
                  additional 506 square feet referred to in the Second
                  Modification of Lease. This termination shall be effective as
                  of February 23, 1999.

         3.       The Premises shall be amended to comprise the approximately
                  2,836.5 rentable square feet referred to in the Modification
                  of Lease (hereinafter

<PAGE>


                  referred to as the "Existing Leased Space") plus the
                  approximately 5,630 rentable square feet, as shown on the
                  floor plan attached to this Third Modification of Lease as
                  Exhibit "A," (hereinafter referred to as the "New Leased
                  Space).

         4.       The Annual Base Rent for the Existing Leased Space shall
                  remain $28,365.00 Net, which shall be made in Monthly
                  Installments of Base Rent of $2,363.75 Net plus Tenant
                  Utilities and other pass throughs as set forth in the Lease
                  Agreement. In addition, Tenant shall continue to pay to
                  Landlord as Additional Rent the amount of $180.46 per month
                  for the Term, which represents reimbursement to Landlord for
                  construction costs toward the preparation of the Existing
                  Leased Space in the total amount of $9,925.00.

         5.       The Base Rent for the New Leased Space shall be a total of
                  $195,565.19 payable as follows:

                  a.    Monthly payments in the amount of $2,345.84 covering the
                        period from February 1, 1999 through July 31, 1999;

                  b.    Monthly payments in the amount of $4,691.68 covering the
                        period from August 1, 1999 through December 31, 1999;

                  c.    Monthly payments in the amount of $5,568.87 covering the
                        period from January 1, 2000 through April 30, 2002, with
                        a payment of $2,103.39 on May 1, 2002.

         6.       Tenant's Proportionate Share, as set forth in paragraph E of
                  the Lease Agreement, shall be amended to be 5.86%.

         7.       The number of parking spaces set forth in paragraph "L" of the
                  Lease Agreement shall be amended to be Thirty-Three (33)
                  Parking Spaces.

         8.       The percentage as set forth in paragraph "M" of the Lease
                  Agreement shall be amended to read 5.86% in all places.

         9.       The per annum figure for Tenant Electric and Gas for the
                  Existing Leased Space set forth in paragraph "M" of the Lease
                  Agreement shall be amended to be $3,545.63. Tenant Electric
                  and Gas expense for the New Leased Space is metered separately
                  and shall be paid directly by Tenant.

         10.      The Effective Date of all changes set forth in this Third
                  Modification of Lease shall be as of February 1, 1999. The
                  Expiration Date of May 11, 2002 set forth in the Lease
                  Agreement shall remain unchanged.

                                       2

<PAGE>


         11.      As to the New Leased Space, Landlord agrees to construct a
                  doorway connection between the Existing Leased Space and the
                  New Leased Space and to paint and clean the carpets in the New
                  Leased Space.

         12.      Except for the foregoing terms, conditions and amendments,
                  this Third Modification of Lease shall be on the same terms,
                  covenants and provisions of the Lease Agreement and the
                  Modification of Lease which are now in effect and which are
                  incorporated herein by reference thereto as if set forth
                  herein at length.

         IN WITNESS WHEREOF, said parties have hereunto set their hands and
seals this 25th day of January, 1999.



WITNESS:                                 RAD Data Communications, Inc.
                                                   Landlord


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


WITNESS:                                 RADVISION, Inc.
                                                  Tenant


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


                                       3

<PAGE>


                          FOURTH MODIFICATION OF LEASE

THIS AGREEMENT, made this 1st day of August, 1999, by and between RAD DATA
COMMUNICATIONS, INC., as Landlord, and RADVISION, INC., as Tenant.

                                   WITNESSETH:

         WHEREAS, the Landlord and Tenant heretofore entered into a Lease
Agreement on May 12, 1997, covering approximately 2,148 square feet of office
space in Lobby 4 of the premises located at 575 Corporate Drive, Mahwah, New
Jersey (the "Lease Agreement"); and

         WHEREAS, the Landlord and Tenant heretofore entered in a Modification
of Lease dated September 10, 1997, (the "Modification of Lease"), by which
Tenant agreed to lease an additional 688.5 square feet in the Building (as
defined in the Lease Agreement) on the terms and conditions set forth therein;
and

         WHEREAS, the Landlord and Tenant heretofore entered into a Second
Modification of Lease dated March 16, 1998, (the "Second Modification of
Lease"), by which Tenant agreed to lease an additional 506 square feet in the
Building (as defined in the Lease Agreement) on the terms and conditions set
forth therein; and

         WHEREAS, the Landlord and Tenant heretofore entered into a Third
Modification of Lease dated January 25, 1999, (the "Third Modification of
Lease"), by which Tenant agreed to terminate the Second Modification of Lease,
such that Tenant would no longer be renting from Landlord the additional 506
square feet referred to in the Second Modification of Lease, on the terms and
conditions set forth therein; and

         WHEREAS,  the term of the Lease  Agreement  commenced  on May 12, 1997
and will expire on May 11, 2002; and

         WHEREAS, the parties desire that Tenant shall rent from Landlord an
additional 506 square feet in the Building (as defined in the Lease Agreement),
which space is adjacent to the Premises (as defined in the Lease Agreement),
under the terms and conditions hereinafter set forth.

         NOW, THEREFORE, the parties hereto agree as follows:

         1.       All defined terms in the Lease Agreement shall have the same
                  meaning in this Fourth Modification of Lease as though set
                  forth herein in full.

<PAGE>


         2.       The Premises shall be amended to include an additional
                  approximately 506 rentable square feet, as shown on the Floor
                  Plan attached to this Fourth Modification of Lease as Exhibit
                  "A" (hereinafter referred to as the "Additional Leased
                  Space").

         3.       The Annual Base Rent for the Additional Leased Space shall be
                  $5,060.00 Net which shall be made in monthly installments of
                  $421.67 Net plus Tenant Utilities and other pass through as
                  set forth in the Lease Agreement.

         4.       Tenant's Proportionate Share as set forth in paragraph "E" of
                  the Lease Agreement shall be amended to read 6.21%, which
                  reflects the addition of .35% as a result of the Additional
                  Leased Space.

         5.       The percentage as set forth in paragraph "M" of the Lease
                  Agreement shall be amended to read 6.21% in all places, which
                  reflects the addition of .35% as a result of the Additional
                  Leased Space.

         6.       The per annum figure for Tenant Electric and Gas set forth in
                  paragraph "M" of the Lease Agreement shall be amended to be
                  $4,178.13. Tenant Electric and Gas expense for the New Leased
                  Space (as referred to in the Third Modification of Lease) is
                  metered separately and shall be paid directly by Tenant.

         7.       The Effective Date of all changes set forth in this Fourth
                  Modification of Lease shall be as of August 1, 1999. The
                  Expiration Date of May 11, 2002 set forth in the Lease
                  Agreement shall remain unchanged.

         8.       Except for the foregoing terms, conditions and amendments,
                  this Fourth Modification of Lease shall be on the same terms,
                  covenants and provisions of the Lease Agreement and the
                  Modification of Lease which are now in effect and which are
                  incorporated herein by reference thereto as if set forth
                  herein at length.

                                       2

<PAGE>


         IN WITNESS WHEREOF, said parties have hereunto set their hands and
seals this 1st day of August, 1999.

WITNESS:                                   RAD Data Communications, Inc.
                                           Landlord


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


WITNESS:                                   RADVISION, Inc.
                                           Tenant


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


                                       3