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                                                                     EXHIBIT 4.6

                                                                        [LOGO]
                                   AROC INC.
                      4200 East Shelly Drive, Suite 1000
                             Tulsa, Oklahoma 74135

                                 June 29, 2001


Dear Stockholders:

     We are offering to purchase any and all of the outstanding shares of our
common stock (the "Shares") from existing stockholders for a purchase price of
$0.06 per share, net to the seller in cash (the "Offer"). THIS OFFER IS NOT
CONDITIONED UPON ANY MINIMUM NUMBER OF SHARES BEING TENDERED.  This Offer was
originally commented on May 14, 2001, and has now been extended until 5:00 p.m.
New York City time, on July 19, 2001, unless further extended or earlier
terminated.  IF YOU HAVE ALREADY TENDERED YOUR SHARES OF AROC COMMON STOCK
PURSUANT TO OUR EARLIER MAILING OF TENDER OFFER DOCUMENTS, NO FURTHER ACTION IS
REQUIRED ON YOUR PART UNLESS YOU WISH TO WITHDRAW YOUR SHARES. IF YOU DO WISH TO
WITHDRAW YOUR SHARES, PLEASE SEE "THE TENDER OFFER--WITHDRAWAL RIGHTS" ON PAGE
25 OF THE OFFER TO PURCHASE.

     Although the offer is being made to all holders of the shares, MPAC
Energy, LLC, our largest stockholder, has advised us that it does not intend to
tender any Shares pursuant to this Offer. MPAC has also advised us that, after
the Offer is consummated, it will pursue a transaction in which AROC will be
taken private and the remaining public stockholders will receive cash for their
shares. As a result, MPAC will own 100% of AROC and we will no longer be a
public company.

     Even if a second-step transaction does not occur, it is nevertheless likely
that the Shares will no longer be quoted on the Pink Sheets Electronic Quotation
Service and AROC will no longer file reports with the SEC.  Under these
circumstances, we would become a private company with all remaining
stockholders, other than MPAC, holding a minority equity position.

     THE PUBLIC MARKET FOR THE SHARES IS VIRTUALLY NONEXISTENT.  WE BELIEVE THAT
THIS MARKET WILL CONTINUE TO BE CHARACTERIZED BY LOW PRICES AND LOW TRADING
VOLUMES FOR THE FORESEEABLE FUTURE.  THIS OFFER PROVIDES THE STOCKHOLDERS WITH
AN OPPORTUNITY TO SELL THEIR SHARES AT A PRICE HIGHER THAN THOSE RECENTLY
AVAILABLE IN THE PUBLIC MARKET.

     The Offer is explained in detailed in the enclosed Offer to Purchase and
Letter of Transmittal.  We encourage you to read these materials carefully
before making any decision with respect to the Offer.  The instructions on how
to tender Shares are also explained in detail in the accompanying materials.

     Prior to the date of this letter, the sales price per share for AROC's
common stock, as reported on June 18, 2001 on the Pink Sheets Electronic
Quotation Service was $0.042.  Any stockholder tendering shares directly to the
Depositary will receive the net purchase price of $0.06 per share in cash and
will not generally incur the usual transaction costs associated with open-market
sales.

     A special committee of the board of directors of AROC (the "Special
Committee"), consisting of the independent director of the board, has determined
that a price of $0.06 per share is fair from a financial point of view to
unaffiliated stockholders.  The Special Committee received a fairness opinion
from its financial advisor, Randall & Dewey, Inc., that a price of $0.06 per
share was fair to the unaffiliated stockholders from a financial point of view.
The Special Committee recommends that the unaffiliated stockholders accept the
Offer and tender their shares pursuant to the Offer.

     The Offer will expire at 5:00 p.m., New York City time, on July 19, 2001,
unless further extended or earlier terminated by AROC.  If you have any
questions or requests for assistance or for additional copies of the Offer to
Purchase, the Letter of Transmittal and the Notice of Guaranteed Delivery, you
may call Registrar and Transfer Company at (800) 368-5948.

                                    Sincerely,


                                    Frank A. Lodzinski
                                    President and Chief Executive Officer