Exhibit 4.6(B)

                           RULE 144A UNIT CERTIFICATE


     THIS UNIT IS A GLOBAL UNIT AND IS REGISTERED IN THE NAME OF A DEPOSITORY OR
A NOMINEE OF A DEPOSITORY OR A SUCCESSOR DEPOSITORY. THIS UNIT IS NOT
EXCHANGEABLE FOR UNITS REGISTERED IN THE NAME OF A PERSON OTHER THAN THE
DEPOSITORY OR ITS NOMINEE EXCEPT IN THE LIMITED CIRCUMSTANCES DESCRIBED IN THE
INDENTURE AND THE WARRANT AGREEMENT HEREINAFTER REFERRED TO, AND NO TRANSFER OF
THIS SECURITY (OTHER THAN A TRANSFER OF THIS SECURITY AS A WHOLE BY THE
DEPOSITORY TO A NOMINEE OF THE DEPOSITORY OR BY A NOMINEE OF THE DEPOSITORY TO
THE DEPOSITORY OR ANOTHER NOMINEE OF THE DEPOSITORY) MAY BE REGISTERED EXCEPT IN
THE LIMITED CIRCUMSTANCES DESCRIBED IN THE INDENTURE AND THE WARRANT AGREEMENT.

     UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE
DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION ("DTC"), TO THE ISSUER OR ITS
AGENT FOR REGISTRATION OF TRANSFER, EXCHANGE, OR PAYMENT, AND ANY CERTIFICATE
ISSUED IS REGISTERED IN THE NAME OF CEDE & CO. OR IN SUCH OTHER NAME AS IS
REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC (AND ANY PAYMENT IS MADE TO
CEDE & CO. OR TO SUCH OTHER ENTITY AS IS REQUESTED BY AN AUTHORIZED
REPRESENTATIVE OF DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR
OTHERWISE BY OR TO ANY PERSON IS WRONGFUL INASMUCH AS THE REGISTERED OWNER
HEREOF, CEDE & CO., HAS AN INTEREST HEREIN.

     THE SECURITIES EVIDENCED HEREBY HAVE NOT BEEN REGISTERED UNDER THE
SECURITIES ACT OF 1933, AS AMENDED (THE "SECURITIES ACT"), OR ANY STATE OR OTHER
SECURITIES LAWS. NEITHER THIS SECURITY NOR ANY INTEREST OR PARTICIPATION HEREIN
MAY BE REOFFERED, SOLD, ASSIGNED, TRANSFERRED, PLEDGED, ENCUMBERED OR OTHERWISE
DISPOSED OF IN THE ABSENCE OF SUCH REGISTRATION OR UNLESS THE TRANSACTION IS
EXEMPT FROM, OR NOT SUBJECT TO, THE REGISTRATION REQUIREMENTS OF THE SECURITIES
ACT. THE HOLDER OF THIS SECURITY BY ITS ACCEPTANCE HEREOF (1) REPRESENTS THAT
(A) IT IS A "QUALIFIED INSTITUTIONAL BUYER" (AS DEFINED IN RULE 144A UNDER THE
SECURITIES ACT ("RULE 144A")) OR (B) IT IS NOT A U.S. PERSON AND IS ACQUIRING
THIS SECURITY IN AN "OFFSHORE TRANSACTION" PURSUANT TO RULE 903 OR 904 OF
REGULATION S UNDER THE SECURITIES ACT ("REGULATION S"), (2) AGREES THAT IT WILL
NOT PRIOR TO (X) THE DATE WHICH IS TWO YEARS (OR SUCH SHORTER PERIOD AS MAY BE
PRESCRIBED BY RULE 144(k) UNDER THE SECURITIES ACT OR ANY SUCCESSOR PROVISION
THEREUNDER) AFTER THE LATER OF THE ORIGINAL ISSUE DATE HEREOF (OR OF ANY
PREDECESSOR OF THIS SECURITY) OR

 
THE LAST DAY ON WHICH THE COMPANY OR ANY AFFILIATE OF THE COMPANY WAS THE OWNER
OF THIS SECURITY OR ANY PREDECESSOR OF THIS SECURITY AND (Y) SUCH LATER DATE, IF
ANY, AS MAY BE REQUIRED BY APPLICABLE LAWS (THE "RESALE RESTRICTION TERMINATION
DATE"), OFFER, SELL OR OTHERWISE TRANSFER THIS SECURITY EXCEPT (A) TO THE
COMPANY, (B) PURSUANT TO A REGISTRATION STATEMENT WHICH HAS BEEN DECLARED
EFFECTIVE UNDER THE SECURITIES ACT, (C) FOR SO LONG AS THE SECURITIES ARE
ELIGIBLE FOR RESALE PURSUANT TO RULE 144A, TO A PERSON IT REASONABLY BELIEVES IS
A "QUALIFIED INSTITUTIONAL BUYER" AS DEFINED IN RULE 144A THAT PURCHASES FOR ITS
OWN ACCOUNT OR FOR THE ACCOUNT OF A QUALIFIED INSTITUTIONAL BUYER TO WHOM NOTICE
IS GIVEN THAT THE TRANSFER IS BEING MADE IN RELIANCE ON RULE 144A, (D) PURSUANT
TO OFFERS AND SALES TO NON-U.S. PERSONS THAT OCCUR OUTSIDE THE UNITED STATES
WITHIN THE MEANING OF REGULATION S, PURSUANT TO RULE 904 OF REGULATION S OR (E)
PURSUANT TO ANOTHER AVAILABLE EXEMPTION FROM THE REGISTRATION REQUIREMENTS OF
THE SECURITIES ACT AND (3) AGREES THAT IT WILL GIVE TO EACH PERSON TO WHOM THIS
SECURITY IS TRANSFERRED A NOTICE SUBSTANTIALLY TO THE EFFECT OF THIS LEGEND.
THIS LEGEND WILL BE REMOVED UPON THE REQUEST OF THE HOLDER AFTER THE RESALE
RESTRICTION TERMINATION DATE. AS USED HEREIN, THE TERMS "OFFSHORE TRANSACTION,"
"UNITED STATES" AND "U.S. PERSON" HAVE THE RESPECTIVE MEANINGS GIVEN TO THEM IN
REGULATION S.

 
                                  WAM!NET INC.

                           -------------------------
                         
                                   GLOBAL UNIT


                                   8,030 Units

            Consisting of $8,030,000 Aggregate Principal at Maturity
                                       of
                     13 1/4% Senior Discount Notes due 2005
                                       and
                    24,090 Warrants To Purchase Common Stock


CUSIP No.  933590 AC 5

REGISTERED No.

     WAM!NET Inc., a Minnesota corporation (the "Company"), hereby certifies
that CEDE & CO., or registered assigns, is the owner of 8,030 Units. Each Unit
consists of (i) $1,000 principal amount at maturity of 13 1/4% Senior Discount
Notes due 2005 of the Company (the "Notes"), and (ii) three Warrants (the
"Warrants"), each Warrant initially entitling the holder thereof to purchase
2.01 shares of Common Stock, par value $.01 per share (the "Common Stock"), of
the Company. The terms of the Notes are governed by an Indenture (as amended
from time to time, the "Indenture") dated as of March 5, 1998 between the
Company and First Trust National Association, a national banking corporation, as
trustee (the "Trustee"), and are subject to the terms and provisions contained
therein. The terms of the Warrants are governed by a Warrant Agreement (as
amended from time to time, the "Warrant Agreement") dated as of March 5, 1998
between the Company and First Trust National Association, a national banking
corporation, as warrant agent (the "Warrant Agent"), and are subject to the
terms and provisions contained therein. The holder of this Unit Certificate
consents to all of the terms and provisions of the Indenture and the Warrant
Agreement by acceptance hereof. The Company will furnish to any Holder of this
Unit Certificate upon written request and without charge a copy of the Indenture
and/or the Warrant Agreement. Requests may be made to: WAM!NET Inc., 6100 West
110th Street, Minneapolis, Minnesota 55438, attention: Secretary.

     The Company hereby appoints First Trust National Association, a national
banking corporation, as Unit Agent (the "Unit Agent") with respect to the Units.
Transfers of this Unit shall be made by the Unit Agent in accordance with the
restrictions set forth in Section 3.17 and Section 3.16 of the Indenture and
Section 1.08 of the Warrant Agreement. The Unit Agent shall be entitled to the
benefits and privileges of the Trustee under the Indenture and the Warrant Agent
under the Warrant Agreement.

 
     The Notes and the Warrants represented by this Unit Certificate will not be
separately transferable until the earliest to occur of: (i) September 1, 1998,
(ii) the occurrence of an Exercise Event (as defined in the Warrant Agreement),
(iii) the occurrence of an Event of Default (as defined in the Indenture), (iv)
the date on which a registration statement under the Securities Act of 1933, as
amended (the "Securities Act"), with respect to a registered exchange offer for
the Notes or covering the sale by holders of the Notes is declared effective
under the Securities Act, (v) immediately prior to any redemption of Notes by
the Company from the net proceeds of an Initial Public Equity Offering (as
defined in the Indenture), (vi) upon the occurrence of a Warrant Change of
Control (as defined in the Warrant Agreement) or (vii) such earlier date as may
be determined by Merrill Lynch & Co. in its sole discretion.


Dated: March 5, 1998                   WAM!NET INC.


                                       By: /s/ Edward J. Driscoll III
                                          --------------------------------
                                       Name:   Edward J. Driscoll III
                                       Title:  President and CEO


Appointment as Unit Agent accepted
  and agreed to on the terms set
  forth above:

FIRST TRUST NATIONAL ASSOCIATION,
  as Unit Agent


By: /s/ Kathe Barrett
   --------------------------------
   Authorized Signatory

 
                                 ASSIGNMENT FORM


If you the holder want to assign this Security, fill in the form below and have
your signature guaranteed:

I or we assign and transfer this Security to
                                            ------------------------------------

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(Insert assignee's social security or tax ID number)

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(Print or type assignee's name, address and zip code) and irrevocably appoint

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agent to transfer this Security on the books of the Company. The agent may
substitute another to act for him.

     In connection with any transfer of this Security occurring prior to the
date which is the earlier of (i) the date of the declaration by the Securities
and Exchange Commission of the effectiveness of a registration statement under
the Securities Act of 1933, as amended (the "Securities Act") covering resales
of this Security (which effectiveness shall not have been suspended or
terminated at the date of the transfer) and (ii) the Resale Restriction
Termination Date, the undersigned confirms that it has not utilized any general
solicitation or general advertising in connection with the transfer and that:

                                   [CHECK ONE]

[ ] (a)  this Security is being transferred in compliance with the exemption 
         from registration under the Securities Act provided by Rule 144A 
         thereunder.

                                       OR

[ ] (b)  this Security is being transferred other than in accordance with
         (a) above and documents are being furnished which comply with the
         conditions of transfer set forth in this Security, the Indenture and
         the Warrant Agreement.

 
If none of the foregoing boxes is checked, the Unit Agent shall not be obligated
to register this Security in the name of any person other than the Holder hereof
unless and until the conditions to any such transfer of registration set forth
herein and in Sections 3.16 and 3.17 of the Indenture and Section 1.08 of the
Warrant Agreement shall have been satisfied.

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Date:                               Your signature:
     -------------                                 -----------------------------
                                                   (Sign exactly as your
                                                   name appears on the
                                                   other side of this
                                                   Security)

Signature Guarantee:
                    ----------------------------

              TO BE COMPLETED BY PURCHASER IF (a) ABOVE IS CHECKED

     The undersigned represents and warrants that it is purchasing this Security
for its own account or an account with respect to which it exercises sole
investment discretion and that it and any such account is a "qualified
institutional buyer" within the meaning of Rule 144A under the Securities Act
and is aware that the sale to it is being made in reliance on Rule 144A and
acknowledges that it has received such information regarding the Company as the
undersigned has requested pursuant to Rule 144A or has determined not to request
such information and that it is aware that the transferor is relying upon the
undersigned's foregoing representations in order to claim the exemption from
registration provided by Rule 144A.

                                              Name of
                                              Purchaser:

Dated:                                        By:
      -----------------                          --------------------------
                                              NOTICE: To be executed by
                                                      an executive officer