Document:

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                                                                   EXHIBIT 10.17

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                          KLINE IRON & STEEL CO., INC.

                             2000 Stock Option Plan

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                               Table of Contents
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1.   PURPOSE................................................................   1

2.   ADMINISTRATION OF THE PLAN.............................................   1

3.   OPTION SHARES..........................................................   2

4.   AUTHORITY TO GRANT OPTIONS.............................................   2

5.   WRITTEN AGREEMENT......................................................   2

6.   ELIGIBILITY............................................................   2

7.   OPTION PRICE...........................................................   3

8.   DURATION OF OPTIONS....................................................   3

9.   VESTING PROVISIONS.....................................................   3

10.  EXERCISE OF OPTIONS....................................................   3

11.  TRANSFERABILITY OF OPTIONS.............................................   5

12.  TERMINATION OF EMPLOYMENT OR INVOLVEMENT OF OPTIONEE WITH THE COMPANY..   5

13.  REQUIREMENTS OF LAW....................................................   6

14.  NO RIGHTS AS STOCKHOLDER...............................................   6

15.  EMPLOYMENT OBLIGATION..................................................   6

16.  FORFEITURE AS A RESULT OF TERMINATION FOR CAUSE........................   6

17.  CHANGES IN THE COMPANY'S CAPITAL STRUCTURE.............................   7

18.  AMENDMENT OR TERMINATION OF PLAN.......................................   8

19.  CERTAIN RIGHTS OF THE COMPANY..........................................   8

20.  GOVERNING LAW..........................................................   9

21.  EFFECTIVE DATE AND DURATION OF THE PLAN................................  10

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                          KLINE IRON & STEEL CO., INC.

                             2000 STOCK OPTION PLAN

     1. PURPOSE

     The purpose of this 2000 Stock Option Plan (the "Plan") is to encourage
directors, officers and employees of and consultants and other persons providing
services to Kline Iron & Steel Co., Inc. (the "Company") and its Affiliates (as
hereinafter defined) to continue their association with the Company and its
Subsidiaries, by providing opportunities for such persons to participate in the
ownership of the Company and in its future growth through the granting of stock
options (the "Options") which may be options designed to qualify as incentive
stock options (within the meaning of Section 422 of the Internal Revenue Code of
1986, as amended (the "Code")) (an "ISO"), or Options not intended to qualify
for any special tax treatment under the Code (a "NQO").  The term "Affiliate" as
used in the Plan means a corporation or other business organization which owns
in the Company, or in which the Company or any such corporation or other
business entity owns, directly or indirectly through an unbroken chain of
ownership, fifty percent (50%) or more of the total combined voting power of all
classes of stock.

     2. ADMINISTRATION OF THE PLAN

     The Plan shall be administered by a committee (the "Committee") consisting
of two or more members of the Company's Board of Directors (the "Board").  The
Committee shall from time to time determine to whom options or other rights
shall be granted under the Plan, whether options granted shall be ISOs or NQOs,
the terms of the options or other rights, and the number of shares that may be
granted under options.  The Committee shall report to the Board the names of
individuals to whom stock or options or other rights are to be granted, the
number of shares covered, and the terms and conditions of each grant.  The
determinations described in this Section 2 may be made by the Committee or by
the Board, as the Board shall direct in its sole and absolute discretion, and
references in the Plan to the Committee shall be understood to refer to the
Board in any such case.

     The Committee shall select one of its members as Chairman and shall hold
meetings at such times and places as it may determine.  A majority of the
Committee shall constitute a quorum, and acts of the Committee at which a quorum
is present, or acts reduced to or approved in writing by all the members of the
Committee, shall be the valid acts of the Committee.  The Committee shall have
the authority to adopt, amend, and rescind such rules and regulations as, in its
opinion, may be advisable in the administration of the Plan.  All questions of
interpretation and application of such rules and regulations, of the Plan and of
Options, shall be subject to the determination of the Committee, which shall be
final and binding.  The Plan shall be administered in such a manner as to permit
those Options granted hereunder and specially designated under Section 5 as ISOs
to qualify as incentive stock options as described in Section 422 of the
Internal Revenue Code of 1986, as amended (the "Code").

     For so long as Section 16 of the Securities Exchange Act of 1934, as
amended from time to time (the "Exchange Act"), is applicable to the Company,
each member of the Committee shall be a "non-employee director" or the
equivalent within the meaning of Rule 16b-3 under the Exchange Act, and, for so
long as Section 162(m) of the Code is applicable to the Company, an "outside
director" within the meaning of Section 162 of the Code and the regulations
thereunder.  If, however, the Committee is not comprised of two or more "outside
directors," then, although the Committee may still administer the Plan, the
Compensation Committee of the Board of Directors of American Tower Corporation,
so long as it is the parent of the Company, or such other committee that makes
grants pursuant to the parent's stock option or similar plan, shall make grants
of options or other rights under the Plan (if the Compensation Committee or such
committee consists of two or more members who are "outside directors").
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     With respect to persons subject to Section 16 of the Exchange Act
("Insiders"), transactions under the Plan are intended to comply with all
applicable conditions of Rule 16b-3 or its successor under the Exchange Act.  To
the extent any provision of the Plan or action by the Committee fails to so
comply, it shall be deemed to be modified so as to be in compliance with such
Rule, or, if such modification is not possible, it shall be deemed to be null
and void, to the extent permitted by law and deemed advisable by the Committee.

     3. OPTION SHARES

     The stock subject to Options under the Plan shall be shares of Common
Stock, par value $.01 per share (the "Stock").  The total amount of the Stock
with respect to which Options may be granted (the "Option Pool"), shall not
exceed in the aggregate 500,000 shares; provided, however, such aggregate number
of shares shall be subject to adjustment in accordance with the provisions of
Section 17.  If an outstanding Option shall expire for any reason or shall
terminate by reason of the death or severance of employment of the Optionee, the
surrender of any such Option, or any other cause, the shares of Stock allocable
to the unexercised portion of such Option may again be subject to an option
under the Plan. The maximum number of shares of Stock subject to Options that
may be granted to any Optionee in the aggregate in any calendar year shall not
exceed 100,000 shares, subject to adjustment in accordance with the provisions
of Section 17.

     4. AUTHORITY TO GRANT OPTIONS

     The Committee may determine, from time to time, which employees of the
Company or any Affiliate or other persons shall be granted Options under the
Plan, the terms of the Options (including without limitation whether an Option
shall be an ISO or a NQO) and the number of shares which may be purchased under
the Option or Options.  Without limiting the generality of the foregoing, the
Committee may from time to time grant:  (a) to such employees (other than
employees of an Affiliate which is not a corporation) as it shall determine an
Option or Options to buy a stated number of shares of Stock under the terms and
conditions of the Plan which Option or Options will to the extent so designated
at the time of grant constitute an ISO; and (b) to such eligible directors,
employees or other persons as it shall determine an Option or Options to buy a
stated number of shares of Stock under the terms and conditions of the Plan
which Option or Options shall constitute a NQO.  Subject only to any applicable
limitations set forth elsewhere in the Plan, the number of shares of Stock to be
covered by any Option shall be as determined by the Committee.

     5. WRITTEN AGREEMENT

     Each Option granted hereunder shall be embodied in an option agreement (the
"Option Agreement") substantially in the form of Exhibit 1, which shall be
signed by the Optionee and by the Chief Executive Officer, the Chief Operating
Officer, Chief Financial Officer, the General Counsel or the Corporate
Controller of the Company for and in the name and on behalf of the Company.  An
Option Agreement may contain such restrictions on exercisability and such other
provisions not inconsistent with the Plan as the Committee in its sole and
absolute discretion shall approve.

     6. ELIGIBILITY

     The individuals who shall be eligible for grant of Options under the Plan
shall be employees (including officers who may be members of the Board),
directors who are not employees and other individuals, whether or not employees,
who render services of special importance to the management, operation or
development of the Company or an Affiliate, and who have contributed or may be
expected to contribute to the success of the Company or an Affiliate.  An
employee, director or other person to

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whom an Option has been granted pursuant to an Option Agreement is hereinafter
referred to as an "Optionee."

     7. OPTION PRICE

     The price at which shares of Stock may be purchased pursuant to an Option
shall be specified by the Committee at the time the Option is granted, but shall
in no event be less than the par value of such shares and, in the case of an
ISO, except as set forth in the following sentence, one hundred percent (100%)
of the fair market value of the Stock on the date the ISO is granted.  In the
case of an employee who owns (or is considered under Section 424(d) of the Code
as owning) stock possessing more than ten percent (10%) of the total combined
voting power of all classes of stock of the Company or any Affiliate, the price
at which shares of Stock may be so purchased pursuant to an ISO shall be not
less than one hundred and ten percent (110%) of the fair value of the Stock on
the date the ISO is granted.

     For purposes of the Plan, the "fair market value" of a share of Stock on
any date specified herein, shall mean (a) the last reported sales price, regular
way, or, in the event that no sale takes place on such day, the average of the
reported closing bid and asked prices, regular way, in either case (i) as
reported on the New York Stock Exchange Composite Tape, or (ii) if the Stock is
not listed or admitted to trading on the New York Stock Exchange, on the
principal national securities exchange on which such security is listed or
admitted to trading, or (iii) if not then listed or admitted to trading on any
national securities exchange, on the NASDAQ National Market System; or (b) if
the Stock is not quoted on such National Market System, (i) the average of the
closing bid and asked prices on each such day in the over-the-counter market as
reported by NASDAQ, or (ii) if bid and asked prices for such security on each
such day shall not have been reported through NASDAQ, the average of the bid and
asked prices for such day as furnished by any New York Stock Exchange member
firm regularly making a market in such security selected for such purpose by the
Committee; or (c) if the Stock is not then listed or admitted to trading on any
national exchange or quoted in the over-the-counter market, the fair value
thereof determined in good faith by the Committee (which shall be entitled to
take into account that the Stock may be illiquid, may be subject to restrictions
on transfer or may constitute a minority interest in the Company); provided,
however, that any method of determining fair market value employed by the
Committee with respect to an ISO shall be consistent with any applicable laws or
regulations pertaining to "incentive stock options."

     8. DURATION OF OPTIONS

     The duration of any Option shall be specified by the Committee in the
Option Agreement, but no Option shall be exercisable after the expiration of ten
(10) years from the date such Option is granted.  In the case of any employee
who owns (or is considered under Section 424(d) of the Code as owning) stock
possessing more than ten percent (10%) of the total combined voting power of all
classes of stock of the Company or any Affiliate, no ISO shall be exercisable
after the expiration of five (5) years from the date such Option is granted.
The Committee, in its sole and absolute discretion, may extend any Option
theretofore granted.

     9. VESTING PROVISIONS

     Each Option may be exercised so long as it is valid and outstanding from
time to time, in part or as a whole, in such manner and subject to such
conditions as the Committee, in its sole and absolute discretion, may provide in
the Option Agreement.  The Committee may, in its sole and absolute discretion,
accelerate Options, in whole or in part, on such terms and conditions as the
Committee may, in its sole and absolute discretion, determine.

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     10. EXERCISE OF OPTIONS

     Options shall be exercised by the delivery of written notice to the Company
setting forth the number of shares of Stock with respect to which the Option is
to be exercised, accompanied by payment of the option price of such shares,
which payment shall be made, subject to the alternative provisions of this
Section, in cash or by such cash equivalents, payable to the order of the
Company in an amount in United States dollars equal to the option price of such
shares, as the Committee in its sole and absolute discretion shall consider
acceptable.  Such notice shall be delivered in person to the Secretary of the
Company or shall be sent by registered mail, return receipt requested, to the
Secretary of the Company, in which case delivery shall be deemed made on the
date such notice is deposited in the mail.

     Alternatively, if the Option Agreement so specifies, and subject to such
rules as may be established by the Committee, payment of the option price may be
made through a so-called "cashless exercise" procedure, under which the Optionee
shall deliver irrevocable instructions to a broker to sell shares of Stock
acquired upon exercise of the Option and to remit promptly to the Company a
sufficient portion of the sale proceeds to pay the option price and any tax
withholding resulting from such exercise.

     Alternatively, payment of the option price may be made, in whole or in
part, in shares of Stock owned by the Optionee; provided, however, that the
Optionee may not make payment in shares of Stock that he acquired upon the
earlier exercise of any ISO (or other "incentive stock option"), unless and
until he has held the shares until at least two (2) years after the date the ISO
(or such other incentive stock option) was granted and at least one (1) year
after the date the ISO (or such other option) was exercised.  If payment is made
in whole or in part in shares of Stock, then the Optionee shall deliver to the
Company in payment of the option price of the shares with respect of which such
Option is exercised (a) certificates registered in the name of such Optionee
representing a number of shares of Stock legally and beneficially owned by such
Optionee, free of all liens, claims and encumbrances of every kind, and having a
fair market value on the date of delivery of such notice equal to the option
price of the shares of Stock with respect to which such Option is to be
exercised, such certificates to be accompanied by stock powers duly endorsed in
blank by the record holder of the shares of Stock represented by such
certificates; and (b) if the option price of the shares with respect to which
such Option is to be exercised exceeds such fair market value, cash or such cash
equivalents payable to the order to the Company, in an amount in United States
dollars equal to the amount of such excess, as the Committee in its sole and
absolute discretion shall consider acceptable.  Notwithstanding the foregoing
provisions of this Section, the Committee, in its sole and absolute discretion,
(i) may refuse to accept shares of Stock in payment of the option price of the
shares of Stock with respect to which such Option is to be exercised and, in
that event, any certificates representing shares of Stock which were delivered
to the Company with such written notice shall be returned to such Optionee
together with notice by the Company to such Optionee of the refusal of the
Committee to accept such shares of Stock and (ii) may accept, in lieu of actual
delivery of stock certificates, an attestation by the Optionee substantially in
the form attached herewith as Exhibit C or such other form as may be deemed
acceptable by the Committee that he or she owns of record the shares to be
tendered free and clear of all liens, claims and encumbrances of every kind.

     Alternatively, if the Option Agreement so specifies, payment of the option
price may be made in part by a full recourse promissory note executed by the
Optionee and containing the following terms and conditions (and such others as
the Committee shall, in its sole and absolute discretion, determine from time to
time):  (a) it shall be collaterally secured by the shares of Stock obtained
upon exercise of the Option; (b) repayment shall be made on demand by the
Company and, in any event, no later than three (3) years from the date of
exercise; and (c) the note shall bear interest at a rate as determined by the
Committee, payable monthly out of a payroll deduction provision; provided,
however, that notwithstanding the foregoing (i) an amount not less than the par
value of the shares of Stock with respect to which the Option is being exercised
must be paid in cash, cash equivalents, or shares of Stock in accordance with
this Section, and (ii) the payment of such exercise price by promissory note
does not violate any applicable laws or regulations, including, without
limitation, Delaware corporate law or applicable margin lending rules.  The
decision as to whether to permit partial payment by a promissory

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note for shares of Stock to be issued upon exercise of any Option granted shall
rest entirely in the sole and absolute discretion of the Committee.

     As promptly as practicable after the receipt by the Company of (a) written
notice from the Optionee setting forth the number of shares of Stock with
respect to which such Option is to be exercised and (b) payment of the option
price of such shares in the form required by the foregoing provisions of this
Section, the Company shall cause to be delivered to such Optionee certificates
representing the number of shares with respect to which such Option has been so
exercised (less a number of shares equal to the number of shares as to which
ownership was attested under the procedure described in clause (ii) of the next
preceding paragraph).

     11. TRANSFERABILITY OF OPTIONS

     Options shall not be transferable by the Optionee otherwise than by will or
under the laws of descent and distribution, and shall be exercisable during his
or her lifetime only by the Optionee, except that the Committee may, subject to
such conditions as it shall, in its sole and absolute discretion, determine,
specify in an Option Agreement that pertains to an NQO that the Optionee may
transfer such NQO to a member of the Immediate Family of the Optionee, to a
trust solely for the benefit of the Optionee and the Optionee's Immediate
Family, or to a partnership or limited liability company whose only partners or
members are the Optionee and members of the Optionee's Immediate Family.
"Immediate Family" shall mean, with respect to any Optionee, such Optionee's
child, stepchild, grandchild, parent, stepparent, grandparent, spouse, sibling,
mother-in-law, father-in-law, son-in-law, daughter-in-law, brother-in-law, or
sister-in-law, and shall include adoptive relationships.

     12. TERMINATION OF EMPLOYMENT OR INVOLVEMENT OF OPTIONEE WITH THE COMPANY

     For purposes of this Section, employment by or involvement with (in the
case of an Optionee who is not an employee) an Affiliate shall be considered
employment by or involvement with the Company.  Except as otherwise set forth in
the Option Agreement, after the Optionee's termination of employment with the
Company other than by reason of death or disability, including his retirement in
good standing from the employ of the Company for reasons of age under the then
established rules of the Company, the Option shall terminate on the earlier of
the date of its expiration or three (3) months after the date of such
termination or retirement.  After the death of the Optionee, his or her
executors, administrators or any persons to whom his or her Option may be
transferred by will or by the laws of descent and distribution shall have the
right to exercise the Option to the extent to which the Optionee was entitled to
exercise the Option.  The Committee may, subject to such conditions as it shall,
in its sole and absolute discretion, determine, specify in an Option Agreement
that, in the event that such termination is a result of disability, the Optionee
shall have the right to exercise the Option pursuant to its terms as if such
Optionee continued as an employee; provided, however, that any such Option that
is an ISO shall, in order to preserve its status as such, be required to be
exercised with twelve (12) months of such termination.

     Authorized leave of absence or absence on military or government service
shall not constitute severance of the employment relationship between the
Company and the Optionee for purposes of the Plan, provided that either (a) such
absence is for a period of no more than ninety (90) days or (b) the Employee's
right to re-employment after such absence is guaranteed either by statute or by
contract.

     For Optionees who are not employees of the Company, options shall be
exercisable for such periods following the termination of the Optionee's
involvement with the Company as may be set forth in the Option Agreement.

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     13. REQUIREMENTS OF LAW

     The Company shall not be required to sell or issue any shares of Stock upon
the exercise of any Option if the issuance of such shares shall constitute or
result in a violation by the Optionee or the Company of any provisions of any
law, statute or regulation of any governmental authority.  Specifically, in
connection with the Securities Act of 1933, as amended (the "Securities Act"),
and any applicable state securities or "blue sky" law (a "Blue Sky Law"), upon
exercise of any Option the Company shall not be required to issue such shares
unless the Committee has received evidence satisfactory to it to the effect that
the holder of such Option will not transfer such shares except pursuant to a
registration statement in effect under the Securities Act and Blue Sky Laws or
unless an opinion of counsel satisfactory to the Company has been received by
the Company to the effect that such registration and compliance is not required.
Any determination in this connection by the Committee shall be final, binding
and conclusive.  The Company shall not be obligated to take any action in order
to cause the exercise of an Option or the issuance of shares of Stock pursuant
thereto to comply with any law or regulations of any governmental authority,
including, without limitation, the Securities Act or applicable Blue Sky Law.

     Notwithstanding any other provision of the Plan to the contrary, the
Company may refuse to permit transfer of shares of Stock if in the opinion of
its legal counsel such transfer would violate federal or state securities laws
or subject the Company to liability thereunder.  Any sale, assignment, transfer,
pledge or other disposition of shares of Stock received upon exercise of any
Option (or any other shares or securities derived therefrom) which is not in
accordance with the provisions of this Section shall be void and of no effect
and shall not be recognized by the Company.

     Legend on Certificates.  The Committee may cause any certificate
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representing shares of Stock acquired upon exercise of an Option (and any other
shares or securities derived therefrom) to bear a legend to the effect that the
securities represented by such certificate have not been registered under the
Securities Act of 1933, as amended, or any applicable state securities laws, and
may not be sold, assigned, transferred, pledged or otherwise disposed of except
in accordance with the Plan and applicable agreements binding the holder and the
Company or any of its stockholders.

     14. NO RIGHTS AS STOCKHOLDER

     No Optionee shall have any rights as a stockholder with respect to shares
covered by his or her Option until the date of issuance of a stock certificate
for such shares; except as otherwise provided in Section 17, no adjustment for
dividends or otherwise shall be made if the record date therefor is prior to the
date of issuance of such certificate.

     15. EMPLOYMENT OBLIGATION

     The granting of any Option shall not impose upon the Company or any
Affiliate any obligation to employ or continue to employ any Optionee, or to
engage or retain the services of any person, and the right of the Company or any
Affiliate to terminate the employment or services of any person shall not be
diminished or affected by reason of the fact that an Option has been granted to
him or her.  The existence of any Option shall not be taken into account in
determining any damages relating to termination of employment or services for
any reason.

     16. FORFEITURE AS A RESULT OF TERMINATION FOR CAUSE

     Notwithstanding any provision of the Plan to the contrary, if the Committee
determines, after full consideration of the facts presented on behalf of the
Company and an Optionee, that

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          (a)  the Optionee has been engaged in fraud, embezzlement, theft,
     commission of a felony or dishonesty in the course of his or her employment
     by or involvement with the Company or an Affiliate, which damaged the
     Company or an Affiliate, or has made unauthorized disclosure of trade
     secrets or other proprietary information of the Company or an Affiliate or
     of a third party who has entrusted such information to the Company or an
     Affiliate, or

          (b)  the Optionee's employment or involvement was otherwise terminated
     for "cause," as defined in any employment agreement with the Optionee, if
     applicable, or if there is no such agreement, as determined by the
     Committee, which may determine that "cause" includes among other matters
     the willful failure or refusal of the Optionee to perform and carry out his
     or her assigned duties and responsibilities diligently and in a manner
     satisfactory to the Committee, or the material breach by the Optionee of
     any rules of conduct, policies or regulations of the Company or any
     Affiliate,

then the Optionee's right to exercise an Option shall terminate as of the date
of such act (in the case of (a)) or such termination (in the case of (b)) and
the Optionee shall forfeit all unexercised Options.  If an Optionee whose
behavior the Company asserts falls within the provisions of (a) or (b) above has
exercised or attempts to exercise an Option prior to a decision of the
Committee, the Company shall not be required to recognize such exercise until
the Committee has made its decision and, in the event of any exercise shall have
taken place, it shall be of no force and effect (and void ab initio) if the
Committee makes an adverse determination; provided, however, if the Committee
finds in favor of the Optionee then the Optionee will be deemed to have
exercised such Option retroactively as of the date he or she originally gave
written notice of his or her attempt to exercise or actual exercise, as the case
may be.  The decision of the Committee as to the cause of an Optionee's
discharge and the damage done to the Company or an Affiliate shall be final,
binding and conclusive.  No decision of the Committee, however, shall affect in
any manner the finality of the discharge of such Optionee by the Company or an
Affiliate.

     17. CHANGES IN THE COMPANY'S CAPITAL STRUCTURE

     The existence of outstanding Options shall not affect in any way the right
or power of the Company or its stockholders to make or authorize any or all
adjustments, recapitalizations, reorganizations or other changes in the
Company's capital structure or its business or any merger or consolidation of
the Company or any issue of bonds, debentures, preferred or preference stock,
whether or not convertible into the Stock or other securities, ranking prior to
the Stock or affecting the rights thereof, or warrants, rights or options to
acquire the same, or the dissolution or liquidation of the Company or any sale
or transfer of all or any part of its assets or business or any other corporate
act or proceeding, whether of a similar character or otherwise.

     The number of shares of Stock in the Option Pool (less the number of shares
theretofore delivered upon exercise of Options) and the number of shares of
Stock covered by any outstanding Option and the price per share payable upon
exercise thereof (provided that in no event shall the option price be less than
the par value of such shares) shall be proportionately adjusted for any increase
or decrease in the number of issued and outstanding shares of Stock resulting
from any subdivision, split, combination or consolidation of shares of Stock or
the payment of a dividend in shares of stock or other securities of the Company
on the Stock.  The decision of the Board as to the adjustment, if any, required
by the provisions of this Section shall be final, binding and conclusive.

     If the Company merges or consolidates with a wholly-owned subsidiary for
the purpose of reincorporating itself under the laws of another jurisdiction,
the Optionees will be entitled to acquire shares of Stock of the reincorporated
Company upon the same terms and conditions as were in effect immediately prior
to such reincorporation (unless such reincorporation involves a change in the
number of shares or the capitalization of the Company, in which case
proportional adjustments shall be made as

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provided above) and the Plan, unless otherwise rescinded by the Board, will
remain the Plan of the reincorporated Company.

     Except as otherwise provided in the preceding paragraph, if the Company is
merged or consolidated with another corporation, whether or not the Company is
the surviving entity, or if the Company is liquidated or sells or otherwise
disposes of all or substantially all of its assets to another entity while
unexercised Options remain outstanding under the Plan, or if other circumstances
occur in which the Board in its sole and absolute discretion deems it
appropriate for the provisions of this paragraph to apply (in each case, an
"Applicable Event"), then (a) each holder of an outstanding Option shall be
entitled, upon exercise of such Option, to receive in lieu of shares of Stock,
such stock or other securities or property as he or she would have received had
he exercised such option immediately prior to the Applicable Event; (b) the
Board may, in its sole and absolute discretion, waive, generally or in one or
more specific cases, any limitations imposed pursuant to Section 9 so that some
or all Options from and after a date prior to the effective date of such
Applicable Event, specified by the Board, in its sole and absolute discretion,
shall be exercisable in full or in part; (c) the Board may, in its sole and
absolute discretion, cancel all outstanding and unexercised Options as of the
effective date of any such Applicable Event; (d) the Board may, in its sole
discretion, convert some or all Options into options to purchase the stock or
other securities of the surviving corporation pursuant to an Applicable Event;
or (e) the Board may, in its sole and absolute discretion, assume the
outstanding and unexercised options to purchase stock or other securities of any
corporation and convert such options into Options to purchase Stock, whether
pursuant to this Plan or not, pursuant to an Applicable Event; provided,
however, notice of any such cancellation pursuant to clause (c) shall be given
to each holder of an Option not less than thirty (30) days preceding the
effective date of such Applicable Event, and provided further, however, that the
Board may, in its sole and absolute discretion, waive, generally or in one or
more specific instances, any limitations imposed pursuant to Section 9 with
respect to any Option so that such Option shall be exercisable in full or in
part during such thirty (30) day period.

     Except as expressly provided herein, the issue by the Company of shares of
Stock or other securities of any class or series or securities convertible into
or exchangeable or exercisable for shares of Stock or other securities of any
class or series for cash or property or for labor or services either upon direct
sale or upon the exercise of rights or warrants to subscribe therefor, or upon
conversion of shares or obligations of the Company convertible into such shares
or other securities, shall not affect, and no adjustment by reason thereof shall
be made with respect to, the number, class or price of shares of Stock then
subject to outstanding Options.

     18. AMENDMENT OR TERMINATION OF PLAN

     The Board may, in its sole and absolute discretion, modify, revise or
terminate the Plan at any time and from time to time; provided, however, that
without the further approval of the holders of at least a majority of the
outstanding shares of Stock, the Board may not change the aggregate number of
shares of Stock which may be issued under Options pursuant to the provisions of
the Plan either to any one person or in the aggregate, or change the class of
persons eligible to receive ISOs.  Notwithstanding the preceding sentence, the
Board shall in all events have the power and authority to make such changes in
the Plan and in the regulations and administrative provisions hereunder or in
any outstanding Option as, in the opinion of counsel for the Company, may be
necessary or appropriate from time to time to enable any Option granted pursuant
to the Plan to qualify as an incentive stock option or such other stock option
as may be defined under the Code, as amended from time to time, so as to receive
preferential federal income tax treatment.

                                      -8-
<PAGE>

     19. CERTAIN RIGHTS OF THE COMPANY

     Voluntary or Involuntary Transfers of Stock.  Except as may be set forth in
     -------------------------------------------
any applicable Optionee/Stockholder Agreement, shares of Stock acquired by an
Optionee pursuant to the exercise of an Option or Options granted under the Plan
shall not be voluntarily transferred by the Optionee without the prior written
consent of the Committee, which consent may be withheld or conditioned as the
Committee, in its sole and absolute discretion, determine.  If such shares of
Stock are subject to an involuntary transfer, including by reason of death, a
divorce settlement or judicial proceeding, the Company shall have the assignable
right to repurchase all or any such shares (including any shares of other
securities of the Company derived therefrom) at a price equal to the Repurchase
Price at the time of the involuntary transfer event.  The Company may exercise
its repurchase right no earlier than one hundred eighty (180) days after the
exercise of the Option (or one or more such exercises) and no later than three
hundred and sixty-five (365) days following the later of (a) the date of such
involuntary transfer of such shares of Stock, and (b) the Committee's receipt of
written notice of the occurrence of such transfer event.  Any such shares of
Stock (or other shares or securities) as to which the Company does not exercise
its repurchase rights within such period shall thereafter be free of the
foregoing restrictions.

     Termination of Employment or Involvement.  If the Optionee's employment by
     ----------------------------------------
or involvement with the Company (including, for this purpose, any Affiliate)
shall terminate for any reason other than the Optionee's death or a Justifiable
Termination (as defined below) or Optionee's retirement for reasons of age or
disability in accordance with the then policy of the Company, the Company shall
have the right to repurchase all or any of such shares of Stock (or other shares
or securities derived therefrom) at a price equal to the Repurchase Price at the
time of such repurchase.  In addition, if at the time of such termination an
Optionee holds an Option granted under the Plan which is by its terms
exercisable after such termination, the Company shall have the assignable right
to repurchase all or any part of the shares of Stock acquired pursuant to the
exercise of such Option, at the Repurchase Price.  In the case of a termination
on account of any circumstance listed in Section 16(a) or (b) (a "Justifiable
Termination"), the Company shall have the right to repurchase all or any of such
shares of Stock at the lesser of (i) the exercise price per share or (ii) the
Repurchase Price at the time of such repurchase.  If the option price for any
repurchased shares has been paid by the Optionee's promissory note pursuant to
Section 10, then the repurchase price for such shares of Stock shall be first
applied to the repayment of the outstanding amount, if any, due under such note
in respect of the repurchased shares, and any accrued but unpaid interest
thereon.   The Company's right to repurchase shares of Stock (or other shares or
securities) may be exercised at any time no later than three hundred and sixty-
five (365) days following the date of the Optionee's termination of employment
or involvement.  Any such shares of Stock (or other shares or securities) as to
which the Company does not exercise its repurchase rights within such period
shall thereafter be free of the foregoing restrictions.

     Repurchase Price.  As used herein the term "Repurchase Price" shall mean
     ----------------
the fair market value of a share of Stock (or other shares or securities) as
determined in accordance with the provisions of Section 7, except that in making
its determination of fair market value of a share of Stock the Committee shall
be entitled to take into account that the shares of Stock (or other shares and
securities) may be illiquid, may be subject to restrictions on transfer or may
constitute a minority interest in the Company.

     Stockholder Agreement.  Unless the Committee shall, in its sole and
     ---------------------
absolute discretion otherwise determine, it shall be a condition of each
Optionee receiving any shares of Stock upon any exercise of an Option that he or
she shall enter into the Optionee/Stockholder Agreement, a copy of which has
heretofore been delivered to the Optionee.

     Other Provisions.  The Committee may, in its sole and absolute discretion,
     ----------------
require a key employee, as a condition to receiving any option, to enter into a
noncompetition agreement in such form as the Committee may, from time to time in
its sole and absolute discretion, determine.

                                      -9-
<PAGE>

     20. GOVERNING LAW

     The Plan shall be governed by and construed and enforced in accordance with
the applicable laws of the United States of America and the law (other than the
law governing conflict of law questions) of The Commonwealth of Massachusetts
except to the extent the laws of any other jurisdiction are mandatorily
applicable.

     21. EFFECTIVE DATE AND DURATION OF THE PLAN

     The Plan shall become effective and shall be deemed to have been adopted on
March 28, 2000.  Unless the Plan shall have terminated earlier, the Plan shall
terminate on the tenth (10th) anniversary of its effective date, and no Option
shall be granted pursuant to the Plan after the day preceding the tenth (10th)
anniversary of its effective date.

                                      -10-<PAGE>

                                                                   Exhibit 10.18
                                                                   -------------

                           AMERICAN TOWER CORPORATION

                       2000 EMPLOYEE STOCK PURCHASE PLAN

1.  PURPOSE

     The purpose of this 2000 Employee Stock Purchase Plan (the "Plan") is to
provide employees of American Tower Corporation (the "Company") and its
Subsidiaries the opportunity to acquire a proprietary interest in the Company by
providing favorable terms for them to purchase its stock.  This Plan is intended
to qualify as an employee stock purchase plan within the meaning of Section 423
of the Code.

2.  DEFINITIONS

(a)   "Board" shall mean the Board of Directors of the Company.

(b)   "Code" shall mean the Internal Revenue Code of 1986, as amended.  Any
reference to a particular Section shall include any successor and regulation
thereto.

(c)   "Committee" shall have the meaning set forth in Section 3.

(d)   "Common Stock" shall mean the shares of the Company's Class A Common
Stock, $0.01 par value per share.

(e)   "Compensation" shall mean the amount reported (or to be reported) in Box 1
of Form W-2, or its equivalent, increased by any salary reduction elected
pursuant to Sections 402(g), 1321(f) or 125 of the Code.

(f)   "Employee" shall mean any individual who has been employed at least 90
days by the Company or any Subsidiary. The term Employee shall not include: (i)
any individual who is not a common law employee of the Company or a Subsidiary;
(ii) any Employee who owns, directly or indirectly, as of the Offering Date five
percent or more of the total combined voting power or value of all class of
stock of the Company or a Subsidiary; (iii) any individual who is a common law
employee of a Subsidiary, none of the employees of which participate in the
Plan, as determined by the Committee; and (iv) any Employee who is a member of
a collective bargaining unit with which the Company or a Subsidiary has
bargained in good faith with respect to participation in the Plan and as a
result of such bargaining the labor organization made an affirmative decision
not to participate in the Plan.

(g)   "Exchange Act" shall mean the Securities Exchange Act of 1934, as amended.

(h)   "Exercise Date" shall mean the date(s) designated by the Committee from
time to time on which an Optionee may exercise an Option; provided, however,
that no Exercise Date shall be more than 12 months after the applicable Offering
Date; and provided, further, that if such date is not a business day, the
Exercise Date shall be the business day immediately preceding the applicable
date.
<PAGE>

(i)   "Fair Market Value" shall be determined according to the following rules:
(i) if the Common Stock is not at the time listed or admitted to trading on a
stock exchange or the Nasdaq National Market, the fair market value shall be the
closing price of the Common Stock on the date in question in the over-the-
counter market, as such price is reported in a publication of general
circulation selected by the Board and regularly reporting the price of the
Common Stock in such market; provided, however, that if the price of the Common
Stock is not so reported, the fair market value shall be determined in good
faith by the Board, which may take into consideration (1) the price paid for the
Common Stock in the most recent trade of a substantial number of shares known to
the Board to have occurred at arm's length between willing and knowledgeable
investors, or (2) an appraisal by an independent party, or (3) any other method
of valuation undertaken in good faith by the Board, or some or all of the above
as the Board shall in its discretion elect; or (ii) if the Common Stock is at
the time listed or admitted to trading on any stock exchange or the Nasdaq
National Market, then the fair market value shall be the mean between the lowest
and highest reported sale prices (or the lowest reported bid price and the
highest reported asked price) of the Common Stock on the date in question on the
principal exchange on which the Common Stock is then listed or admitted to
trading. If no reported sale of Common Stock takes place on the date in question
on the principal exchange or the Nasdaq National Market, as the case may be,
then the reported closing sale price (or the reported closing asked price) of
the Common Stock on the prior trading date immediately preceding such date on
the principal exchange or the Nasdaq National Market, as the case may be, shall
be determinative of fair market value.

(j)   "Insider" shall mean a person subject to Section 16 of the Exchange Act.

(k)   "Offering" shall mean any offering of Common Stock in accordance with
Section 7.

(l)   "Offering Date" shall mean the date(s) designated by the Committee from
time to time on which an Option is granted; provided, however, that there shall
be at least one Offering Date in any consecutive 12-month period while the Plan
remains in effect; and provided, further, that if such date is not a business
day, the Offering Date shall be the business day immediately preceding the
applicable date.

(m)   "Option" shall mean the right of a Participant to purchase Common Stock
pursuant to an Offering.

(n)   "Option Price" shall have the meaning set forth in Section 8.

(o)   "Optionee" shall mean any individual who has been granted an Option that
remains outstanding under the terms of any Offering or who owns Common Stock as
a result of an Offering.

(p)   "Participant" shall mean an Employee who has in effect a payroll deduction
authorization in accordance with Section 6.

(q)   "Securities Act" shall mean the Securities Act of 1933, as amended.

(r)   "Subsidiary" shall mean a corporation of which the Company owns, directly
or indirectly through an unbroken chain of ownership, fifty percent or more of
the total combined voting power of all classes of stock, whether or not such
corporation now exists or is hereafter organized or acquired by the Company or a
Subsidiary.

                                     - 2 -
<PAGE>

3.  ADMINISTRATION OF THE PLAN

     The Plan shall be administered by the Board or, in the discretion of the
Board, a committee composed of at least two individuals who may be members of
the Board or employees of the Company or a Subsidiary (the "Committee").  In the
event that a vacancy on the Committee occurs on account of the resignation of a
member or the removal of a member by vote of the Board, a successor member shall
be appointed by vote of the Board.  No member of the Committee shall be liable
for any action or determination made in good faith with respect to the Plan.
All references in the Plan to the "Committee" shall be understood to refer to
the Committee or the Board, whoever shall administer the Plan.

     The Committee shall select one of its members as Chairman and shall hold
meetings at such times and places as it may determine.  A majority of the
Committee shall constitute a quorum, and acts of the Committee at which a quorum
is present, or acts reduced to or approved in writing by all the members of the
Committee, shall be the valid acts of the Committee.  The Committee shall have
the authority to adopt, amend and rescind such rules and regulations as, in its
opinion, may be advisable in the administration of the Plan.  All questions of
interpretation and application of such rules and regulations, of the Plan and of
Options granted thereunder shall be subject to the determination of the
Committee, which shall be final and binding.

     The Committee shall have the authority, without the need for further
approval, to establish a different Offering Date and/or Exercise Date, to modify
the amount of time between an Offering Date and an Exercise Date and to increase
or decrease the number of Offerings in a year.

     With respect to Insiders, transactions under the Plan are intended to
comply with all applicable conditions of Rule 16b-3 or its successor under the
Exchange Act.  To the extent any provision of the Plan or action by the
Committee fails to so comply, it shall be deemed to be modified so as to be in
compliance with such Rule or, if such modification is not possible, it shall be
deemed to be null and void, to the extent permitted by law and deemed advisable
by the Committee.

4.  OPTION SHARES

     The total amount of Common Stock with respect to which Options may be
granted under the Plan shall not exceed in the aggregate 5,000,000 shares from
either authorized but unissued shares or treasury shares; provided, however,
that such aggregate number of shares shall be subject to adjustment in
accordance with Section 15.  If any outstanding Option expires for any reason,
including a withdrawal pursuant to Section 10, or terminates by reason of the
severance of employment of the Participant or any other cause, or is
surrendered, the shares of Common Stock allocable to the unexercised portion of
the Option may again be made subject to an Option under the Plan.

5.  ELIGIBILITY

     An Employee shall be eligible to become a Participant in the Plan on any
Offering Date on which the Employee is employed by the Company or a Subsidiary;
provided, however, that no Employee shall be granted an Option:

                                     - 3 -
<PAGE>

      (i)  if immediately after the grant the aggregate amount of stock the
   Employee would be considered to own under Section 424(d) of the Code,
   including stock that may be purchased with outstanding options, would
   represent five percent or more of the total combined voting power or value of
   all classes of capital stock of the Company or of any Subsidiary; or

      (ii) that permits the Employee's right to purchase shares under all
   employee stock purchase plans (within the meaning of Section 423 of the Code)
   of the Company and its Subsidiaries to accrue at a rate that exceeds $25,000
   for any calendar year, determined by reference to the Fair Market Value of
   the shares at the time any option is granted.

6.  PARTICIPATION

   (a) An Employee may become a Participant in any Offering by completing an
authorization for payroll deductions in connection with the Offering at such
time (prior to the Offering Date) and in such manner as the Committee may
prescribe. Payroll deductions pursuant to an authorization shall commence with
the payroll period in which the Offering Date occurs and shall end with the last
payroll completed prior to the Exercise Date for the Offering to which the
authorization applies, unless the authorization is sooner terminated by the
Participant as provided in Section 10. The Committee may provide that in the
case of the first Offering, payroll deductions shall commence with the first
payroll period ending after the initial Offering Date. All payroll deductions
shall be made on an after-tax basis.

    (b) A Participant shall elect in the authorization for payroll deduction to
have deductions made from his or her Compensation on each payday in an amount
equal to a whole percentage of from one to fifteen percent of his Compensation.
All payroll deductions made for a Participant shall be credited to a bookkeeping
account maintained for such Participant under the Plan. In no event shall
interest be paid to a Participant with respect to payroll deductions credited to
the Participant's account, whether such deductions are used in connection with
the exercise of an Option or are returned to the Participant or the
Participant's estate in cash.

    (c)  Except as may be required by law, a Participant may not make any
payments to the Participant's account other than by authorization for payroll
deduction. A Participant may elect to decrease the payroll deduction rate at
such time and in such manner as the Committee may prescribe. In no event shall a
Participant increase the amount of payroll deductions during an Offering. A
Participant may discontinue participation in the Offering as provided in Section
10.

7.  GRANT OF OPTIONS

    (a)  Options under the Plan shall be granted in a series of Offerings, the
first of which shall begin on the first Offering Date designated by the
Committee. Successive Offerings shall begin on each Offering Date thereafter
until all of the shares of Common Stock available under the Plan are exhausted
or until the Plan is terminated pursuant to Section 18 or Section 19.
Participation by an Employee in any Offering shall neither limit nor require his
participation in any other Offering.

    (b)  Each Participant in an Offering shall be granted, as of the applicable
Offering Date, an Option to purchase that number of whole shares of Common Stock
that the accumulated payroll deductions credited to his account during the
Offering is able to purchase at the Option Price.

                                     - 4 -
<PAGE>

    (c)  If the total number of shares for which Options are to be granted as of
any Offering Date exceeds the number of shares then available under the Plan,
the Committee shall make a pro rata allocation of the available shares in a
manner as nearly uniform as practicable, and as it shall determine to be
equitable. In that event, the payroll deductions made or to be made pursuant to
authorizations for that Offering shall be reduced accordingly, and the Committee
shall give written notice of such reduction to each affected Participant.

    (d)  In no event shall a Participant be granted an Option in any Offering to
acquire more than that number of whole shares of Common Stock equal to $25,000
divided by the Fair Market Value of the shares as of the Offering Date;
provided, however, that such limit shall be subject to Section 5(ii) and to the
adjustment in accordance with Section 15.

8.  OPTION PRICE

     The Option Price of shares of Common Stock for any Offering shall be the
lesser of: (a) 85 percent of the Fair Market Value of the shares on the Offering
Date; or (b) 85 percent of the Fair Market Value of the shares on the Exercise
Date.

9.  EXERCISE OF OPTIONS

    (a)  A Participant's Option for an Offering will be exercised automatically
as of the Exercise Date for the Offering to purchase that number of whole shares
of Common Stock equal to the accumulated payroll deductions credited to the
Participant's account as of the Exercise Date divided by the Option Price.

    (b)  As promptly as practicable after each Exercise Date the Company shall
deliver to each Participant in the Offering, in accordance with the
Participant's election, either (a) the shares purchased upon the exercise of the
Participant's Option, together with a cash payment equal to the balance of any
payroll deductions credited to the Participant's account during the Offering
that were not used for the purchase of shares, other than amounts representing
fractional shares, or (b) a cash payment equal to the total of the payroll
deductions credited to the Participant's account during the Offering. Amounts
representing fractional shares will, at the discretion of the Committee, either
be carried forward for use in the next Offering if the Participant will
participate in that Offering or paid to the Participant in cash.

    (c)  The shares purchased upon exercise of an Option shall be deemed to be
transferred to the Participant on the Exercise Date.

10.  WITHDRAWAL FROM OFFERING

     A Participant may at any time prior to the Exercise Date at such time and
in such manner as the Committee may prescribe withdraw from an Offering and
request payment of an amount in cash equal to the accumulated payroll deductions
credited to the Participant's account under the Plan.  Such amount will be paid
to the Participant as promptly as practicable after receipt of

                                     - 5 -
<PAGE>

the Participant's request to withdraw, and no further payroll deductions will be
made from the Participant's Compensation with respect to the Offering then in
progress and any outstanding Option shall be cancelled. A Participant's
withdrawal from an Offering will have no effect upon his or her eligibility to
participate in any subsequent Offering or in any employee stock purchase plan
(within the meaning of Section 423 of the Code) that may hereafter be adopted by
the Company or a Subsidiary.

11.  EXPIRATION OF OPTIONS ON TERMINATION OF EMPLOYMENT

     Options shall not be transferable by a Participant and no amount credited
to a Participant's account may be assigned, transferred, pledged or otherwise
disposed of in any way by a Participant.  An Option shall expire unexercised
immediately if a Participant ceases to satisfy the definition of the term
Employee for any reason other than death and the amount of the accumulated
payroll deductions then credited to the Participant's account under the Plan
will be paid in cash.  Upon termination of the Participant's employment with the
Company or a Subsidiary for any reason other than death, an amount in cash equal
to the accumulated payroll deductions then credited to the Participant's account
under the Plan will be paid to the Participant.  In the case of a Participant's
death, the provisions of Section 15 shall control.

     An authorized leave of absence or absence on military or government service
shall not constitute severance of the employment relationship between the
Company or Subsidiary and the Participant for purposes of this Section 11,
provided that either (a) the absence is for a period of no more than 90 days
or (b) the Employee's right to be re-employed after the absence is guaranteed
either by statute or by contract.

12.  REQUIREMENTS OF LAW

     The Company shall not be required to sell or issue any shares of Common
Stock under the Plan if the issuance of such shares would constitute or result
in a violation by the Optionee or the Company of any provision of any law,
statute or regulation of any governmental authority.  Specifically, in
connection with the Securities Act, upon the exercise of any Option the Company
shall not be required to issue shares unless the Board has received evidence
satisfactory to it to the effect that the Optionee will not transfer such shares
except pursuant to a registration statement in effect under the Securities Act
or unless an opinion of counsel satisfactory to the Company has been received by
the Company to the effect that such registration is not required.  Any
determination in this connection by the Board shall be final, binding and
conclusive.  The Company shall not be obligated to take any affirmative action
to cause the exercise of an Option or the issuance of shares pursuant to an
Option to comply with any laws or regulations of any governmental authority
including, without limitation, the Securities Act or applicable state securities
laws.

13.  NO RIGHTS AS STOCKHOLDER

     No Participant shall have rights as a stockholder with respect to shares
covered by his Option until the applicable Exercise Date and, except as
otherwise provided in Section 15, no adjustment shall be made for dividends of
which the record date precedes the applicable Exercise Date.

                                     - 6 -
<PAGE>

14.  FORFEITURE FOR DISHONESTY

     Notwithstanding anything to the contrary in the Plan, if the Board
determines, after full consideration of the facts presented on behalf of both
the Company and the individual, that a Participant or an Optionee has been
engaged in fraud, embezzlement, theft, commission of a felony or proven
dishonesty in the course of the individual's employment by the Company or a
Subsidiary, or has disclosed trade secrets or other proprietary information of
the Company or a Subsidiary, (a) such individual's participation in an Offering
shall terminate and the individual shall forfeit the right to receive any Common
Stock pursuant to an Offering that has not yet been delivered and (b) the
Company shall have the right to repurchase all or any part of the shares of
Common Stock acquired by an Optionee upon the earlier exercise of any Option, at
a price equal to the amount paid to the Company upon such exercise, increased by
an amount equal to the interest that would have accrued in the period between
the date of exercise of the Option and the date of such repurchase upon a debt
in the amount of the exercise price, at the prime rate(s) announced from time to
time during such period in the Federal Reserve Statistical Release Selected
Interest Rates.  The decision of the Board as to the cause of a Participant's or
Optionee's discharge and the damage done to the Company or a Subsidiary shall be
final, binding and conclusive.  No decision of the Board, however, shall affect
in any manner the finality of the discharge of a Participant or Optionee by the
Company or a Subsidiary.

15.  CHANGES IN THE COMPANY'S CAPITAL STRUCTURE

    (a)  If the outstanding shares of Common Stock are hereafter changed for a
different number or kind of shares or other securities of the Company, by reason
of a reorganization, recapitalization, exchange of shares, stock split,
combination of shares or dividend payable in shares or other securities, a
corresponding adjustment shall be made by the Committee in the number and kind
of shares or other securities, and in the Option Price, covered by outstanding
Options, and for which Options may be granted under the Plan; provided, however,
that no adjustment shall be made that would constitute a modification as defined
in Section 424 of the Code. Any such adjustment made by the Committee shall be
conclusive and binding upon all affected persons, including the Company and all
Participants and Optionees.

    (b)  If while unexercised Options remain outstanding under the Plan the
Company merges or consolidates with a wholly-owned subsidiary for the purpose of
reincorporating itself under the laws of another jurisdiction, the Optionees
will be entitled to acquire shares of common stock of the reincorporated Company
upon the same terms and conditions as were in effect immediately prior to such
reincorporation (unless such reincorporation involves a change in the number of
shares or the capitalization of the Company, in which case proportional
adjustments shall be made as provided above), and the Plan, unless otherwise
rescinded by the Board, will remain the Plan of the reincorporated company.

    (c)  Except as otherwise provided in (a) or (b) above, if while unexercised
Options remain outstanding under the Plan the Company merges or consolidates
with one or more corporations (whether or not the Company is the surviving
corporation), or is liquidated or sells or otherwise disposes of substantially
all of its assets to another entity, then the Committee, in its discretion,
shall provide that either:

                                     - 7 -
<PAGE>

         (i) after the effective date of such merger, consolidation,
   liquidation or sale, as the case may be, each Optionee shall be entitled,
   upon exercise of an Option to receive in lieu of shares of Common Stock the
   number and class of shares of such stock or other securities to which he
   would have been entitled pursuant to the terms of the merger, consolidation,
   liquidation or sale if he had been the holder of record of the number of
   shares of Common Stock as to which the Option is being exercised immediately
   prior to such merger consolidation, liquidation or sale; or

         (ii)  all outstanding Options shall be exercised as of the day
   preceding the effective date of any such merger, consolidation, liquidation
   or sale, which day shall be the Exercise Date for purposes of the Offering;
   provided, however, that each Optionee shall be notified of the right to
   withdraw from the Offering in accordance with the requirements of Section 10.

    (d)  Except as expressly provided to the contrary in this Section 15, the
issuance by the Company of shares of stock of any class for cash or property or
for services, either upon direct sale or upon the exercise of rights or
warrants, or upon conversion of shares or obligations of the Company convertible
into such shares or other securities, shall not affect the number, class or
price of shares of Common Stock then subject to outstanding Options.

16.  DISPOSITION OF ACCOUNT AT DEATH

     In the event that a Participant dies after the Exercise Date but before the
delivery of the stock certificates, such certificates when issued together with
any cash remaining in the Participant's account shall be transferred to the
Participant's estate.  In the event that a Participant dies prior to the
Exercise Date, a payment shall be made to the Participant's estate of an amount
in cash equal to the accumulated payroll deductions credited to the
Participant's account under the Plan; provided, however, that the executor,
administrator or personal representative of the estate of the Participant may by
notice to the Committee in the form and manner prescribed by the Committee
request that the balance of the Participant's account shall be used to exercise
on the Exercise Date the outstanding Option granted prior to the Participant's
death.  Any such election by the executor, administrator or personal
representative shall be made not later than the Exercise Date.  The Company
shall transfer such shares and any cash remaining in the Participant's account
to the executor, administrator or personal representative of the estate of the
Participant.

17.  MISCELLANEOUS

     (a) Accumulated payroll deductions and the proceeds from the sale of shares
pursuant to the exercise of Options shall constitute general funds of the
Company.

     (b) To the extent required by law, the Company or a Subsidiary shall
withhold or cause to be withheld income and other taxes with respect to any
income recognized by an Optionee by reason of the exercise of an Option. An
Optionee shall agree that if the amount payable to him by the Company and any
Subsidiary in the ordinary course is insufficient to pay such taxes, then he
shall upon request of the Company pay to the Company an amount sufficient to
satisfy its tax withholding obligations.

                                     - 8 -
<PAGE>

(c)   All notices or other communications by a Participant or Optionee to the
Company pursuant to the Plan shall be deemed to have been given when received in
the form specified by the Company at the location or by the person designated by
the Company for the receipt thereof.

(d)   Neither the Plan nor the grant of an Option pursuant to the Plan shall
impose upon the Company or a Subsidiary any obligation to employ or continue to
employ any Participant, and the right of the Company or a Subsidiary to
terminate the employment of any person shall not be diminished or affected by
reason of the fact that an Option has been granted to him.

(e)   The title of the sections of the Plan are included for convenience only
and shall not be construed as modifying or affecting their provisions. The
masculine gender shall include both sexes; the singular shall include the plural
and the plural the singular unless the context otherwise requires.

(f)   The Plan shall be governed by and construed in accordance with the laws of
the Commonwealth of Massachusetts, without regard to the principles of conflicts
of law.

18.  AMENDMENT OR TERMINATION OF PLAN

     The Board may at any time terminate or from time to time amend, modify or
suspend this Plan (or any part thereof); provided, however, that without
approval by holders of a majority of the outstanding shares of common stock
present, or represented, and entitled to vote thereon (voting as a single class)
at a duly held meeting (or written consents in lieu thereof) of the shareholders
of the Company there shall be no:  (a) change in the number of shares of Common
Stock that may be issued under the Plan, except by operation of the provisions
of Section 15; (b) change in the class of persons eligible to participate in the
Plan; or (c) other change in the Plan that requires stockholder approval under
applicable law. Notwithstanding the preceding sentence, the Board shall in all
events have the power to make such changes in the Plan and the Committee shall
in all events have the power to make such changes in the regulations and
administrative provisions under the Plan or in any outstanding Option as, in the
opinion of counsel for the Company, may be necessary or appropriate from time to
time to enable the Plan to qualify as an employee stock purchase plan as defined
in Section 423 of the Code, so as to enable any Option to receive preferential
federal income tax treatment. No amendment shall materially affect outstanding
Options without the consent of the Optionee and the termination of the Plan will
not terminate Options then outstanding, without the consent of the Optionee.

     Notwithstanding the foregoing, at such time after the Company is not
required to file periodic reports under the Exchange Act, at its option, the
Company may terminate the Plan and, upon the termination, outstanding Options
shall be cancelled and each Participant shall receive in cash an amount equal to
the accumulated payroll deductions without interest credited to the
Participant's account under the Plan immediately prior to termination.

                                     - 9 -
<PAGE>

19.  EFFECTIVE DATE AND DURATION OF THE PLAN

     The Plan shall be effective as of July 1, 2000, subject only to
ratification by the holders of a majority of the outstanding shares of common
stock present, or represented, and entitled to vote thereon (voting as a single
class) at a duly held meeting (or written consents in lieu thereof) of the
shareholders of the Company within 12 months before or after such date. Unless
the Plan shall have terminated earlier, the Plan shall terminate on the business
date as of which there are no longer any shares available pursuant to Section 4
to be offered and no Option shall be granted pursuant to the Plan after that
date.

                                     - 10 -

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