EXHIBIT 3.1
 
               AMENDED AND RESTATED CERTIFICATE OF INCORPORATION
                                       OF
                               CUNO INCORPORATED
                               -----------------


           (Original Certificate of Incorporation filed May 22, 1985)


     CUNO Incorporated (the "CORPORATION"), originally incorporated as AMF
Specialty Materials Inc., a corporation organized and existing under and by
virtue of the General Corporation Law of the State of Delaware (the "DGCL"),
does hereby certify that the Amended and Restated Certificate of Incorporation
of the Corporation set forth below has been duly adopted in accordance with
Sections 242 and 245 of the DGCL:


                                   ARTICLE I
                                   ---------

     The name of the corporation is CUNO Incorporated (the "CORPORATION").


                                  ARTICLE II
                                  ----------

     The address of the Corporation's registered office in the State of Delaware
is Corporation Trust Center, 1209 Orange St., Wilmington, County of New Castle,
Delaware 19801.  The name of the Corporation's registered agent at such address
is The Corporation Trust Company.


                                  ARTICLE III
                                  -----------

     The nature of the business to be conducted or promoted is to engage in any
lawful act or activity for which corporations may be organized under the DGCL.


                                  ARTICLE IV
                                  ----------

     A.  Authorized Stock
         ----------------

          1.  The Corporation shall have authority to issue the following
     classes of stock, in the number of shares and at the par value as indicated
     opposite the name of the class:

 


                                                          NUMBER OF
                                                            SHARES                    PAR VALUE
                        CLASS                             AUTHORIZED                  PER SHARE
         -------------------------------              -----------------           ----------------
                                                                                
                     Common Stock                         50,000,000                  $0.001

                   Preferred Stock                         2,000,000                  $0.001
 

     B.   The designations and the powers, preferences and relative, 
participating, or other rights of the capital stock and optional the 
qualifications, limitations or restrictions thereof are as follows:
                                        
     1.   Common Stock.
          ------------ 

          a.  Voting Rights:  Except as otherwise required by law or expressly
     provided herein, the holders of shares of Common Stock shall be entitled to
     one vote per share on each matter submitted to a vote of the stockholders
     of the Corporation.

          b.  Dividends:  Subject to the rights of the holders, if any, of
     Preferred Stock, the holders of Common Stock shall be entitled to receive
     dividends at such times and in such amounts as may be determined by the
     Board of Directors of the Corporation.

          c.  Liquidation Rights:  In the event of any liquidation, dissolution
     or winding up of the Corporation, whether voluntary or involuntary, after
     payment or provision for payment of the debts and other liabilities of the
     Corporation and the preferential amounts to which the holders of any
     outstanding shares of Preferred Stock shall be entitled upon dissolution,
     liquidation or winding up, the assets of the Corporation available for
     distribution to stockholders shall be distributed ratably among the holders
     of the shares of Common Stock.

     2.   Preferred Stock.
          --------------- 

          Preferred Stock may be issued from time to time in one or more series.
     Subject to the other provisions of this Certificate of Incorporation and
     any limitations prescribed by law, the Board of Directors is authorized to
     provide for the issuance of and issue shares of the Preferred Stock in
     series and, by filing a certificate pursuant to the laws of the State of
     Delaware, to establish from time to time the number of shares to be
     included in each such series and to fix the designation, powers,
     preferences and rights of the shares of each such series and any
     qualifications, limitations or restrictions thereof.


                                   ARTICLE V
                                   ---------

     The business and affairs of the Corporation shall be managed by or under
the direction of a board of directors consisting of not less than five (5) nor
more than twelve (12) directors. The

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exact number shall be determined from time to time by resolution adopted by the
affirmative vote of a majority of the directors in office at the time of
adoption of such resolution. Initially, the number of directors shall be 
five (5) and shall consist of the following persons: John M. Galvin, 
Mark G. Kachur, Gerald C. McDonough, C. Edward Midgley and Paul J. Powers.

     The directors shall be divided into three classes, Class I, Class II and
Class III; with Class I having one member and each of Class II and Class III
having two members. Class I shall initially consist of the following director:
John M. Galvin. Class II shall initially consist of the following directors:
Mark G. Kachur and Gerald C. McDonough . Class III shall initially consist of
the following directors: C. Edward Midgley and Paul J. Powers. The initial term
of office of the Class I, Class II and Class III directors shall expire at the
annual meeting of stockholders in 1997, 1998 and 1999, respectively. Beginning
in 1997, at each annual meeting of stockholders, successors to the class of
directors whose term expires at that annual meeting shall be elected for a 
three-year term. If the number of directors is changed, any increase or 
decrease shall be apportioned among the classes by the Board of Directors so 
as to maintain the number of directors in each class as nearly equal as is
reasonably possible, and any additional director of any class elected to fill
a vacancy resulting from an increase in such class shall hold office for a term
that shall coincide with the remaining term of that class. In no case will a
decrease in the number of directors shorten the term of any incumbent director
even though such decrease may result in an inequality of the classes until the
expiration of such term. A director shall hold office until the annual meeting
of the year in which his or her term expires and until his or her successor
shall be elected and shall qualify, subject, however, to prior death,
resignation, retirement or removal from office. Subject to the rights of the
holders of any series of Preferred Stock with respect to such series of
Preferred Stock, any director, or the entire Board of Directors, may be removed
from office at any time, but only for cause and only by the affirmative vote of
the holders of at least 80 percent of the voting power of the shares entitled to
vote generally in the election of directors. Except as required by law or the
provisions of this Certificate of Incorporation, all vacancies on the Board of
Directors and newly-created directorships shall be filled by the Board of
Directors. Any director elected to fill a vacancy not resulting from an increase
in the number of directors shall have the same remaining term as that of his or
her predecessor.

     Notwithstanding the foregoing, whenever the holders of any one or more
classes or series of Preferred Stock issued by the Corporation shall have the
right, voting separately by class or series, to elect directors at an annual or
special meeting of stockholders, the election, term of office, filling of
vacancies and other features of such directorship shall be governed by the terms
of this Certificate of Incorporation and any resolutions of the Board of
Directors applicable thereto, and such directors so elected shall not be divided
into classes pursuant to this Article V. Notwithstanding anything to the
contrary contained in this Certificate of Incorporation, the affirmative vote of
the holders of at least eighty percent (80%) of the voting power of the shares
entitled to vote generally in the election of directors shall be required to
amend, alter or repeal, or to adopt any provision inconsistent with, this
Article V.

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                                  ARTICLE VI
                                  ----------

     A.   No Written Consent. Any action required or permitted to be taken by
the stockholders of the Corporation shall be effected at a duly called annual or
special meeting of stockholders of the Corporation and shall not be effected by
consent in writing by the holders of outstanding stock pursuant to Section 228
of the DGCL or any other provision of the DGCL.

     B.   Special Meetings. Special meetings of stockholders of the Corporation
may be called upon not less than 10 nor more than 60 days' written notice only
by the Board of Directors pursuant to a resolution approved by a majority of the
Board of Directors.

     C.   Amendment. Notwithstanding anything contained in this Certificate of
Incorporation to the contrary, the affirmative vote of the holders of at least
eighty percent (80%) of the shares entitled to vote generally in the election of
directors shall be required to amend, alter or repeal, or to adopt any provision
inconsistent with, this Article VI.


                                  ARTICLE VII
                                  -----------

     In furtherance and not in limitation of the power conferred by statute, the
Board of Directors is expressly authorized to make, alter, amend or repeal the
By-laws of the Corporation. The By-laws of the Corporation may be altered,
amended, or repealed, or new By-laws may be adopted, by the Board of Directors
in accordance with the preceding sentence or by the vote of the holders of at
least two-thirds of the voting power of the shares of the Corporation entitled
to be cast generally in the election of directors at an annual or special
meeting of stockholders, provided that if such alteration, amendment, repeal or
adoption of new By-laws is effected at a duly called special meeting, notice of
such alteration, amendment, repeal or adoption of new By-laws is contained in
the notice of such special meeting.


                                 ARTICLE VIII
                                 ------------

     A director of the Corporation shall not in the absence of fraud be
disqualified by his office from dealing or contracting with the Corporation
either as a vendor, purchaser or otherwise, nor in the absence of fraud shall a
director of the Corporation be liable to account to the Corporation for any
profit realized by him from or through any transaction or contract of the
Corporation by reason of the fact that he, or any firm of which he is a member
or any corporation of which he is an officer, director or stockholder, was
interested in such transaction or contract if such transaction or contract has
been authorized, approved or ratified in a manner provided in the DGCL for
authorization, approval or ratification of transactions or contracts between the
Corporation and one or more of its directors or officers or between the
Corporation and any other corporation, partnership, association or other
organization in which one or more of its directors or officers are directors or
officers or have a financial interest.

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                                  ARTICLE IX
                                  ----------

     Meetings of stockholders may be held within or without the State of
Delaware as the By-laws may provide. The books of the Corporation may be kept
outside the State of Delaware at such place or places as may be designated from
time to time by the Board of Directors of the Corporation or in the By-laws of
the Corporation. Election of directors need not be by written ballot unless the
By-laws of the Corporation so provide.

                                   ARTICLE X
                                   ---------

     Whenever a compromise or arrangement is proposed between this Corporation
and its creditors or any class of them and/or between this Corporation and its
stockholders or any class of them, any court of equitable jurisdiction within
the State of Delaware may, on the application in a summary way of this
Corporation or of any creditor or stockholder thereof or on the application of
any receiver or receivers appointed for this Corporation under the provisions of
Section 291 of the DGCL or on the application of trustees in dissolution or of
any receiver or receivers appointed for the Corporation under the provisions of
Section 279 of the DGCL, order a meeting of the creditors or class of creditors
and/or the stockholders or class of stock of the Corporation, as the case may
be, to be summoned in such manner as the said court directs. If a majority in
number representing two-thirds of the value of the creditors or class of
creditors and/or the stockholders or class of stockholders of this Corporation,
as the case may be, agree to any compromise or arrangement or to any
reorganization of this Corporation as a consequence of such compromise or
arrangement, the said compromise or arrangement of the said reorganization
shall, if sanctioned by the Court to which the said application has been made,
be binding on all the creditors or class of creditors and/or on all the
stockholders or class of stockholders, of this Corporation, as the case may be,
and also on this Corporation.


                                  ARTICLE XI
                                  ----------

     The Board of Directors of the Corporation may adopt a resolution proposing
to amend, alter, change or repeal any provision contained in this Certificate of
Incorporation, in the manner now or hereafter prescribed by statute.


                                  ARTICLE XII
                                  -----------

     A.   Indemnification of Officers and Directors:  The Corporation shall:

          1.  indemnify, to the fullest extent permitted by the DGCL, any
     director and any officer, employee or agent of the Corporation selected by
     the Board of Directors for indemnification, such selection to be evidenced
     by an indemnification agreement, who was or is a party or is threatened to
     be made a party to any threatened, pending or completed action, suit or
     proceeding, whether civil, criminal, administrative or

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     investigative (other than an action by or in the right of the Corporation)
     by reason of the fact that such person is or was a director, or is or was
     serving at the request of the Corporation as a director, officer, employee
     or agent of another corporation, partnership, joint venture, trust or other
     enterprise, or if such person has previously been designated for
     indemnification by a resolution of the Board of Directors, an officer,
     employee or agent of the Corporation, against expenses (including
     attorneys' fees), judgments, fines and amounts paid in settlement actually
     and reasonably incurred by such person in connection with such action, suit
     or proceeding if such person acted in good faith and in a manner such
     person reasonably believed to be in or not opposed to the best interests of
     the Corporation, and, with respect to any criminal action or proceeding,
     had no reasonable cause to believe such person's conduct was unlawful. The
     termination of any action, suit or proceeding by judgment, order,
     settlement, conviction, or upon a plea of nolo contendere or its
     equivalent, shall not, of itself, create a presumption that the person did
     not act in good faith and in a manner which such person reasonably believed
     to be in or not opposed to the best interests of the Corporation, and, with
     respect to any criminal action or proceeding, had reasonable cause to
     believe that such person's conduct was unlawful; and

          2.   indemnify any director and any officer, employee or agent of the
     Corporation selected by the Board of Directors for indemnification, such
     selection to be evidenced by an indemnification agreement, who was or is a
     party or is threatened to be made a party to any threatened, pending or
     completed action or suit by or in the right of the Corporation to procure a
     judgment in its favor by reason of the fact that such person is or was a
     director, or is or was serving at the request of the Corporation as a
     director, officer, employee or agent of another corporation, partnership,
     joint venture, trust or other enterprise, or if such person has previously
     been designated for indemnification by a resolution of the Board of
     Directors, an officer, employee or agent of the Corporation, against
     expenses (including attorneys' fees) actually and reasonably incurred by
     him in connection with the defense or settlement of such action or suit if
     such person acted in good faith and in a manner such person reasonably
     believed to be in or not opposed to the best interests of the Corporation
     and except that no indemnification shall be made in respect of any claim,
     issue or matter as to which such person shall have been adjudged to be
     liable to the Corporation unless and only to the extent that the Court of
     Chancery or the court in which such action or suit was brought shall
     determine upon application that, despite the adjudication of liability but
     in view of all the circumstances of the case, such person is fairly and
     reasonably entitled to indemnity for such expenses which the Court of
     Chancery or such other court shall deem proper; and

          3.   indemnify any director, officer, employee or agent against
     expenses (including attorneys' fees) actually and reasonably incurred by
     such person in connection therewith, to the extent that such director,
     officer, employee or agent of the Corporation has been successful on the
     merits or otherwise in defense of any action, suit or

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     proceeding referred to in Article XII.A. (a) and (b), or in defense of any
     claim, issue or matter therein; and

          4.   make any indemnification under Article XII.A. (a) and (b) (unless
     ordered by a court) only as authorized in the specific case upon a
     determination that indemnification of the director, officer, employee or
     agent is proper in the circumstances because such director, officer,
     employee or agent has met the applicable standard of conduct set forth in
     Article XII.A. (a) and (b). Such determination shall be made (1) by the
     Board of Directors by a majority vote of a quorum consisting of directors
     who were not parties to such action, suit or proceeding, or (2) if such a
     quorum is not obtainable, or, even if obtainable a quorum of disinterested
     directors so directs, by independent legal counsel in a written opinion, or
     (3) by the stockholders of the Corporation; and

          5.   pay expenses incurred by a director or officer in defending a
     civil or criminal action, suit or proceeding in advance of the final
     disposition of such action, suit or proceeding upon receipt of an
     undertaking by or on behalf of such director or officer to repay such
     amount if it shall ultimately be determined that such director or officer
     is not entitled to be indemnified by the Corporation as authorized in this
     Article XII. Notwithstanding the foregoing, the Corporation shall not be
     obligated to pay expenses incurred by a director or officer with respect to
     any threatened, pending, or completed claim, suit or action, whether civil,
     criminal, administrative, investigative or otherwise ("Proceedings")
     initiated or brought voluntarily by a director or officer and not by way of
     defense (other than Proceedings brought to establish or enforce a right to
     indemnification under the provisions of this Article XII unless a court of
     competent jurisdiction determines that each of the material assertions made
     by the director or officer in such proceeding were not made in good faith
     or were frivolous). The Corporation shall not be obligated to indemnify the
     director or officer for any amount paid in settlement of a Proceeding
     covered hereby without the prior written consent of the Corporation to such
     settlement; and

          6.   not deem the indemnification and advancement of expenses provided
     by, or granted pursuant to, the other subsections of this Article XII as
     exclusive of any other rights to which those seeking indemnification or
     advancement of expenses may be entitled under any by-law, agreement, vote
     of stockholders or disinterested directors or otherwise, both as to action
     in such director's or officer's official capacity and as to action in
     another capacity while holding such office; and

          7.   have the right, authority and power to purchase and maintain
     insurance on behalf of any person who is or was a director, officer,
     employee or agent of the Corporation, or is or was serving at the request
     of the Corporation as a director, officer, employee or agent of another
     corporation, partnership, joint venture, trust or other enterprise against
     any liability asserted against such person and incurred by such person in
     any such capacity, or arising out of such person's status as such, whether
     or not the

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     Corporation would have the power to indemnify such person against such
     liability under the provisions of this Article XII; and

          8.   deem the provisions of this Article XII to be a contract between
     the Corporation and each director, or appropriately designated officer,
     employee or agent who serves in such capacity at any time while this
     Article XII is in effect and any repeal or modification of this Article XII
     shall not affect any rights or obligations then existing with respect to
     any state of facts then or theretofore existing or any action, suit or
     proceeding theretofore or thereafter brought or threatened based in whole
     or in part upon such state of facts.  The provisions of this Article XII
     shall not be deemed to be a contract between the Corporation and any
     directors, officers, employees or agents of any other Corporation (the
     "Second Company") which shall merge into or consolidate with this
     Corporation when this Corporation shall be the surviving or resulting
     Corporation, and any such directors, officers, employees or agents of the
     Second Company shall be indemnified to the extent required under the DGCL
     only at the discretion of the board of directors of this Corporation; and

          9.   continue the indemnification and advancement of expenses provided
     by, or granted pursuant to, this Article XII, unless otherwise provided
     when authorized or ratified, as to a person who has ceased to be a
     director, officer, employee or agent of the Corporation and shall inure to
     the benefit of the heirs, executors and administrators of such a person.


     B.   Elimination of Certain Liability of Directors:  No director of the
Corporation shall be personally liable to the Corporation or its stockholders
for monetary damages for breach of fiduciary duty as a director, except for
liability (i) for any breach of the director's duty of loyalty to the
Corporation or its stockholders, (ii) for acts or omissions not in good faith or
which involve intentional misconduct or a knowing violation of law, (iii) under
Section 174 of the DGCL, as the same exists or hereafter may be amended, or (iv)
for any transaction from which the director derived an improper personal
benefit.  If the DGCL is amended to authorize the further elimination or
limitation of liability of directors, then the liability of a director of the
Corporation, in addition to the limitation on personal liability provided
herein, shall be limited to the fullest extent permitted by the amended DGCL.
Any repeal or modification of this Article XII by the stockholders of the
Corporation shall be prospective only, and shall not adversely affect any
limitation on the personal liability of a director of the Corporation existing
at the time of such repeal or modification.

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     IN WITNESS WHEREOF, the Corporation has caused this Amended and Restated
Certificate of Incorporation to be signed on July __, 1996.



                                       CUNO INCORPORATED


                                    By:______________________________________
                                       [Name]
                                       [Title]

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