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                                                                     EXHIBIT 4.1


                             Mykrolis Corporation

                          2001 EQUITY INCENTIVE PLAN

1.  DEFINED TERMS

    Exhibit A, which is incorporated by reference, defines the terms used in
the Plan and sets forth certain operational rules related to those terms.

2.  GENERAL

    The Plan has been established to advance the interests of the Company by
giving Stock-based and other incentives to selected Employees, directors and
other persons (including both individuals and entities) who provide services to
the Company or its Affiliates.

3.  ADMINISTRATION

    The Administrator has discretionary authority, subject only to the express
provisions of the Plan, to interpret the Plan; determine eligibility for and
grant Awards; determine, modify or waive the terms and conditions of any Award;
prescribe forms, rules and procedures (which it may modify or waive); and
otherwise do all things necessary to carry out the purposes of the Plan.  Once
an Award has been communicated in writing to a Participant, the Administrator
may not, without the Participant's consent, alter the terms of the Award so as
to affect adversely the Participant's rights under the Award, unless the
Administrator expressly reserved the right to do so.  In the case of any Award
intended to be eligible for the performance-based compensation exception under
Section 162(m), the Administrator shall exercise its discretion consistent with
qualifying the Award for such exception.

4.  LIMITS ON AWARD UNDER THE PLAN

a.  Number of Shares.

    A maximum of (1) [    ] shares of Stock, plus (2) an annual increase to be
added on the date of each annual meeting of the stockholders of the Company,
beginning with the 2002 annual meeting of the stockholders, equal to one percent
(1.0%) of the outstanding shares of Stock on such date or such lesser amount
determined by the Board, may be delivered in satisfaction of Awards under the
Plan.  The shares of Stock may be authorized, but unissued, or reacquired shares
of Stock.  For purposes of the preceding sentence, the following shares shall
not be considered to have been delivered under the Plan:  (i)  shares remaining
under an Award that terminates without having been exercised in full;  (ii)
shares subject to an Award,

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where cash is delivered to a Participant in lieu of such shares; (iii) shares of
Restricted Stock that have been forfeited in accordance with the terms of the
applicable Award; and (iv) shares held back, in satisfaction of the exercise
price or tax withholding requirements, from shares that would otherwise have
been delivered pursuant to an Award. The number of shares of Stock delivered
under an Award shall be determined net of any previously acquired Shares
tendered by the Participant in payment of the exercise price or of withholding
taxes. A maximum of [ ] shares of Stock may be issued as ISO Awards under the
Plan.

    b.  Type of Shares.

    Stock delivered by the Company under the Plan may be authorized but
unissued Stock or previously issued Stock acquired by the Company and held in
treasury.  No fractional shares of Stock will be delivered under the Plan.

    c.  Option & SAR Limits.

    The maximum number of shares of Stock for which Stock Options may be
granted to any person in any calendar year, the maximum number of shares of
Stock subject to SARs granted to any person in any calendar year and the
aggregate maximum number of shares of Stock subject to other Awards that may be
delivered to any person in any calendar year shall each be 1,000,000.  For
purposes of the preceding sentence, the repricing of a Stock Option or SAR shall
be treated as a new grant to the extent required under Section 162(m).  Subject
to these limitations, each person eligible to participate in the Plan shall be
eligible in any year to receive Awards covering up to the full number of shares
of Stock then available for Awards under the Plan.

    d.  Other Award Limits.

    No more than $1,000,000 may be paid to any individual with respect to any
Cash Performance Award.  In applying the limitation of the preceding sentence:
(A) multiple Cash Performance Awards to the same individual that are determined
by reference to performance periods of one year or less ending with or within
the same fiscal year of the Company shall be subject in the aggregate to one
limit of such amount, and (B) multiple Cash Performance Awards to the same
individual that are determined by reference to one or more multi-year
performance periods ending in the same fiscal year of the Company shall be
subject in the aggregate to a separate limit of such amount.  With respect to
any Performance Award other than a Cash Performance Award or a Stock Option or
SAR, the maximum Award opportunity shall be 1,000,000 shares of Stock or their
equivalent value in cash, subject to the limitations of Section 4.c.



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5.  ELIGIBILITY AND PARTICIPATION

    The Administrator will select Participants from among those key Employees,
directors and other individuals or entities providing services to the Company or
its Affiliates who, in the opinion of the Administrator, are in a position to
make a significant contribution to the success of the Company and its
Affiliates.  Eligibility for ISOs is further limited to those individuals whose
employment status would qualify them for the tax treatment described in Sections
421 and 422 of the Code.

6.  RULES APPLICABLE TO AWARDS

All Awards. Terms of Awards.  The Administrator shall determine the terms of all
Awards subject to the limitations provided herein.  In the case of an ISO, the
term shall be ten (10) years from the date of grant or such shorter term as may
be provided in the Award. Moreover, in the case of an ISO granted to a
Participant who, at the time the ISO is granted, owns stock representing more
than ten percent (10%) of the total combined voting power of all classes of
capital stock of the Company or any Parent or Subsidiary, the term of the ISO
shall be five (5) years from the date of grant or such shorter term as may be
provided in the Award.

Performance Criteria.  Where rights under an Award depend in whole or in part on
satisfaction of Performance Criteria, actions by the Company that have an
effect, however material, on such Performance Criteria or on the likelihood that
they will be satisfied will not be deemed an amendment or alteration of the
Award.

Alternative Settlement.  The Company may at any time extinguish rights under an
Award in exchange for payment in cash, Stock (subject to the limitations of
Section 4) or other property on such terms as the Administrator determines,
provided the holder of the Award consents to such exchange.

         (1)  Transferability Of Awards. Except as the Administrator otherwise
expressly provides, Awards may not be transferred other than by will or by the
laws of descent and distribution, and during a Participant's lifetime an Award
requiring exercise may be exercised only by the Participant (or in the event of
the Participant's incapacity, the person or persons legally appointed to act on
the Participant's behalf).

         (2)  Vesting, Etc. Without limiting the generality of Section 3, the
Administrator may determine the time or times at which an Award will vest (i.e.,
become free of forfeiture restrictions) or become exercisable and the terms on
which an Award requiring exercise will remain exercisable. Unless the
Administrator expressly provides otherwise, immediately upon the cessation of
the Participant's employment or other service relationship with the Company and
its Affiliates an Award requiring exercise will cease to be exercisable and all
Awards to the extent not already fully vested will be forfeited, except that:

              (A) all Stock Options and SARs held by a Participant immediately
         prior to his or her death, to the extent then exercisable, will remain
         exercisable by such Participant's executor or administrator or the
         person or persons to


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         whom the Stock Option or SAR is transferred by will or the applicable
         laws of descent and distribution, and to the extent not then
         exercisable will vest and become exercisable upon such Participant's
         death by such Participant's executor or administrator or the person or
         persons to whom the Stock Option or SAR is transferred by will or the
         applicable laws of descent and distribution, in each case for the
         lesser of (i) a one year period ending with the first anniversary of
         the Participant's death or (ii) the period ending on the latest date on
         which such Stock Option or SAR could have been exercised without regard
         to this Section 6.a.(5) and shall thereupon terminate;

              (B) all Stock Options and SARs held by the Participant immediately
         prior to the cessation of the Participant's employment or other service
         relationship for reasons other than death and except as provided in (C)
         below, to the extent then exercisable, will remain exercisable for the
         lesser of (i) a period of three months or (ii) the period ending on the
         latest date on which such Stock Option or SAR could have been exercised
         without regard to this Section 6.a.(5), and shall thereupon terminate;
         and

              (C) all Stock Options and SARs held by the Participant whose
         cessation of employment or other service relationship is determined by
         the Administrator in its sole discretion to result for reasons which
         cast such discredit on the Participant as to justify immediate
         termination of the Award shall immediately terminate upon such
         cessation.

Unless the Administrator expressly provides otherwise, a Participant's
"employment or other service relationship with the Company and its Affiliates"
will be deemed to have ceased, in the case of an employee Participant, upon
termination of the Participant's employment with the Company and its Affiliates
(whether or not the Participant continues in the service of the Company or its
Affiliates in some capacity other than that of an employee of the Company or its
Affiliates), and in the case of any other Participant, when the service
relationship in respect of which the Award was granted terminates (whether or
not the Participant continues in the service of the Company or its Affiliates in
some other capacity).

Taxes.  The Administrator will make such provision for the withholding of taxes
as it deems necessary.  The Administrator may, but need not, hold back shares of
Stock from an Award or permit a Participant to tender previously owned shares of
Stock in satisfaction of tax withholding requirements, but not in excess of the
minimum tax withholding rates applicable to the employee.

         (3)  Dividend Equivalents, Etc. The Administrator may provide for the
payment of amounts in lieu of cash dividends or other cash distributions with
respect to Stock subject to an Award.



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         (4)  Rights Limited. Nothing in the Plan shall be construed as giving
any person the right to continued employment or service with the Company or its
Affiliates, or any rights as a shareholder except as to shares of Stock actually
issued under the Plan. The loss of existing or potential profit in Awards will
not constitute an element of damages in the event of termination of employment
or service for any reason, even if the termination is in violation of an
obligation of the Company or Affiliate to the Participant.

         (5)  Section 162(m). In the case of an Award intended to be eligible
for the performance-based compensation exception under Section 162(m), the Plan
and such Award shall be construed to the maximum extent permitted by law in a
manner consistent with qualifying the Award for such exception.

    b.   Awards Requiring Exercise.Time And Manner Of Exercise. Unless the
         Administrator expressly provides otherwise, (a) an Award requiring
         exercise by the holder will not be deemed to have been exercised until
         the Administrator receives a written notice of exercise (in form
         acceptable to the Administrator) signed by the appropriate person and
         accompanied by any payment required under the Award; and (b) if the
         Award is exercised by any person other than the Participant, the
         Administrator may require satisfactory evidence that the person
         exercising the Award has the right to do so.

         (1)  Exercise Price. The Administrator shall determine the exercise
price of each Stock Option provided that each Stock Option intended to qualify
for the performance-based exception under Section 162(m) of the Code and each
ISO must have an exercise price that is not less than the fair market value of
the Stock subject to the Stock Option, determined as of the date of grant. An
ISO granted to an Employee described in Section 422(b)(6) of the Code must have
an exercise price that is not less than 110% of such fair market value.

         (2)  Payment Of Exercise Price, If Any. Where the exercise of an Award
is to be accompanied by payment: (a) all payments will be by cash or check
acceptable to the Administrator, or, if so permitted by the Administrator (with
the consent of the optionee of an ISO if permitted after the grant), (i) through
the delivery of shares of Stock which have been outstanding for at least six
months (unless the Administrator approves a shorter period) and which have a
fair market value equal to the exercise price, (ii) by delivery of a promissory
note of the person exercising the Award to the Company, payable on such terms as
are specified by the Administrator, (iii) by delivery of an unconditional and
irrevocable undertaking by a broker to deliver promptly to the Company
sufficient funds to pay the exercise price, or (iv) by any combination of the
foregoing permissible forms of payment; and (b) where shares of Stock issued
under an Award are part of an original issue of shares, the Award shall require
an exercise price equal to at least the par value of such shares.

         (3)  ISOs. No ISO may be granted under the Plan after [ ], 2011, but
ISOs previously granted may extend beyond that date.



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    c. Awards Not Requiring Exercise.

    Awards of Restricted Stock and Unrestricted Stock may be made in return for
either (i) services determined by the Administrator to have a value not less
than the par value of the Awarded shares of Stock, or (ii) cash or other
property having a value not less than the par value of the Awarded shares of
Stock payable in such combination and type of cash, other property (of any kind)
or services as the Administrator may determine.

7.  EFFECT OF CERTAIN TRANSACTIONS

    a.  Mergers, Etc.

    In the event of a Covered Transaction, all outstanding Awards shall vest
and if relevant become exercisable and all deferrals, other than deferrals of
amounts that are neither measured by reference to nor payable in shares of
Stock, shall be accelerated, immediately prior to the Covered Transaction and
upon consummation of such Covered Transaction all Awards then outstanding and
requiring exercise shall be forfeited unless assumed by an acquiring or
surviving entity or its affiliate as provided in the following sentence.  In the
event of a Covered Transaction, unless otherwise determined by the
Administrator, all Awards that are payable in shares of Stock and that have not
been exercised, exchanged or converted, as applicable, shall be converted into
and represent the right to receive the consideration to be paid in such Covered
Transaction for each share of Stock into which such Award is exercisable,
exchangeable or convertible, less the applicable exercise price or purchase
price for such Award.  In connection with any Covered Transaction in which there
is an acquiring or surviving entity, the Administrator may provide for
substitute or replacement Awards from, or the assumption of Awards by, the
acquiring or surviving entity or its affiliates, any such substitution,
replacement or assumption to be on such terms as the Administrator determines,
provided that no such replacement or substitution shall diminish in any way the
acceleration of Awards provided for in this section.

    b.  Changes in and Distributions with Respect to the Stock.Basic Adjustment
        Provisions. In the event of a stock dividend, stock split or combination
        of shares, recapitalization or other change in the Company's capital
        structure after [_____], 2001, the Administrator will make appropriate
        adjustments to the maximum number of shares that may be delivered under
        the Plan under Section 4.a., and will also make appropriate adjustments
        to the number and kind of shares of stock or securities subject to
        Awards then outstanding or subsequently granted, any exercise prices
        relating to Awards and any other provision of Awards affected by such
        change.

        Certain Other Adjustments. The Administrator may also make adjustments
        of the type described in paragraph (1) above to take into account
        distributions to common stockholders other than those provided for in
        Section 7.a. and 7.b.(1), or any other event, if the Administrator
        determines that adjustments are appropriate to avoid distortion in the
        operation of the Plan and to preserve the


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         value of Awards made hereunder; provided, that no such adjustment shall
         be made to the maximum share limits described in Section 4.c. or 4.d.,
         or otherwise to an Award intended to be eligible for the performance-
         based exception under Section 162(m), except to the extent consistent
         with that exception, nor shall any change be made to ISOs except to the
         extent consistent with their continued qualification under Section 422
         of the Code.

         (1)  Continuing Application of Plan Terms. References in the Plan to
shares of Stock shall be construed to include any stock or securities resulting
from an adjustment pursuant to Section 7.b.(1) or 7.b.(2) above.

8.  LEGAL CONDITIONS ON DELIVERY OF STOCK

    The Company will not be obligated to deliver any shares of Stock pursuant
to the Plan or to remove any restriction from shares of Stock previously
delivered under the Plan until the Company's counsel has approved all legal
matters in connection with the issuance and delivery of such shares; if the
outstanding Stock is at the time of delivery listed on any stock exchange or
national market system, the shares to be delivered have been listed or
authorized to be listed on such exchange or system upon official notice of
issuance; and all conditions of the Award have been satisfied or waived.  If the
sale of Stock has not been registered under the Securities Act of 1933, as
amended, the Company may require, as a condition to exercise of the Award, such
representations or agreements as counsel for the Company may consider
appropriate to avoid violation of such Act.  The Company may require that
certificates evidencing Stock issued under the Plan bear an appropriate legend
reflecting any restriction on transfer applicable to such Stock.

9.  AMENDMENT AND TERMINATION

    Subject to the last sentence of Section 3, the Administrator may at any
time or times amend the Plan or any outstanding Award for any purpose which may
at the time be permitted by law, or may at any time terminate the Plan as to any
further grants of Awards; provided, that (except to the extent expressly
required or permitted by the Plan) no such amendment will, without the approval
of the stockholders of the Company, effectuate a change for which stockholder
approval is required in order for the Plan to continue to qualify under Section
422 of the Code and for Awards to be eligible for the performance-based
exception under Section 162(m).

10. NON-LIMITATION OF THE COMPANY'S RIGHTS

    The existence of the Plan or the grant of any Award shall not in any way
affect the Company's right to Award a person bonuses or other compensation in
addition to Awards under the Plan.

11. GOVERNING LAW

    The Plan shall be construed in accordance with the laws of the State of
Delaware.



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                                   EXHIBIT A

Definition of Terms

     The following terms, when used in the Plan, shall have the meanings and be
subject to the provisions set forth below:

     "Administrator":  The Board or, if one or more has been appointed, the
Committee.

     "Affiliate":  Any corporation or other entity owning, directly or
indirectly, 50% or more of the outstanding Stock of the Company, or in which the
Company or any such corporation or other entity owns, directly or indirectly,
50% of the outstanding capital stock (determined by aggregate voting rights) or
other voting interests.

     "Award":  Any or a combination of the following:

          (i)    Stock Options.

          (ii)   SARs.

          (iii)  Restricted Stock.

          (iv)   Unrestricted Stock.

          (v)    Deferred Stock.

          (vi)   Securities (other than Stock Options) that are convertible into
     or exchangeable for Stock on such terms and conditions as the Administrator
     determines.

          (vii)  Cash Performance Awards.

          (viii) Performance Awards.

          (ix)   Grants of cash, or loans, made in connection with other Awards
     in order to help defray in whole or in part the economic cost (including
     tax cost) of the Award to the Participant.

     "Board":  The Board of Directors of the Company.

     "Cash Performance Award":  A Performance Award payable in cash.  The right
of the Company under Section 6.a.(3) to extinguish an Award in exchange for cash
or the


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exercise by the Company of such right shall not make an Award otherwise not
payable in cash a Cash Performance Award.

     "Code":  The U.S. Internal Revenue Code of 1986 as from time to time
amended and in effect, or any successor statute as from time to time in effect.

     "Committee":  One or more committees of the Board which in the case of
Awards granted to officers of the Company shall be comprised solely of two or
more outside directors within the meaning of Section 162(m).  Any Committee may
delegate ministerial tasks to such persons (including Employees) as it deems
appropriate.

     "Company":  Mykrolis Corporation

     "Covered Transaction":  Any of (i) a consolidation or merger in which the
Company is not the surviving corporation or which results in the acquisition of
all or substantially all of the Company's then outstanding common stock by a
single person or entity or by a group of persons and/or entities acting in
concert, (ii) a sale or transfer of all or substantially all the Company's
assets, or (iii) a dissolution or liquidation of the Company.

     "Deferred Stock":  A promise to deliver Stock or other securities in the
future on specified terms.

     "Employee":  Any person who is employed by the Company or an Affiliate.

     "ISO":  A Stock Option intended to be an "incentive stock option" within
the meaning of Section 422 of the Code.  No Stock Option Awarded under the Plan
will be an ISO unless the Administrator expressly provides for ISO treatment.

     "Parent":  A "parent corporation," whether now or hereafter existing, as
defined in Section 424(e) of the Code.

     "Participant":  An Employee, director or other person providing services to
the Company or its Affiliates who is granted an Award under the Plan.

     "Performance Award":  An Award subject to Performance Criteria.  The
Committee in its discretion may grant Performance Awards that are intended to
qualify for the performance-based compensation exception under Section 162(m)
and Performance Awards that are not intended so to qualify.

     "Performance Criteria":  Specified criteria the satisfaction of which is a
condition for  the exercisability, vesting or full enjoyment of an Award.  For
purposes of Performance Awards that are intended to qualify for the performance-
based compensation exception under Section 162(m), a Performance Criterion shall
mean an objectively determinable measure of performance relating to any of the
following (determined either on a consolidated basis or, as



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the context permits, on a divisional, subsidiary, line of business, project or
geographical basis or in combinations thereof): (i) sales; revenues; assets;
expenses; earnings before or after deduction for all or any portion of interest,
taxes, depreciation, amortization or other items, whether or not on a continuing
operations or an aggregate or per share basis; return on equity, investment,
capital or assets; one or more operating ratios; borrowing levels, leverage
ratios or credit rating; market share; capital expenditures; cash flow; stock
price; stockholder return; network deployment; sales of particular products or
services; customer acquisition, expansion and retention; or any combination of
the foregoing; or (ii) acquisitions and divestitures (in whole or in part);
joint ventures and strategic alliances; spin-offs, split-ups and the like;
reorganizations; recapitalizations, restructurings, financings (issuance of debt
or equity) and refinancings; transactions that would constitute a change of
control; or any combination of the foregoing. A Performance Criterion measure
and targets with respect thereto determined by the Administrator need not be
based upon an increase, a positive or improved result or avoidance of loss.

     "Plan":  The Mykrolis Corporation 2001 Equity Incentive Plan, as from time
to time amended and in effect.

     "Restricted Stock":  An Award of Stock subject to restrictions requiring
that such Stock be redelivered to the Company if specified conditions are not
satisfied.

     "Section 162(m)":  Section 162(m) of the Code.

     "SARs":  Rights entitling the holder upon exercise to receive cash or
Stock, as the Administrator determines, equal to a function (determined by the
Administrator using such factors as it deems appropriate) of the amount by which
the Stock has appreciated in value since the date of the Award.

     "Stock":  Common Stock of the Company, par value $ .01 per share.

     "Stock Options":  Options entitling the recipient to acquire shares of
Stock upon payment of the exercise price.

     "Subsidiary":  A "subsidiary corporation," whether now or hereafter
existing, as defined in Section 424(f) of the Code.

     "Unrestricted Stock":  An Award of Stock not subject to any restrictions
under the Plan.



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