EXHIBIT 4.7

ITEM 1. DESCRIPTION OF SECURITIES TO BE REGISTERED

     On April 21, 1999, Input/Output, Inc. (the "Company") and Harris Trust and
Savings Bank, as Rights Agent (the "Rights Agent") entered into the First
Amendment ("Amendment No. 1") to the Rights Agreement (the "Rights Agreement"),
dated as of January 17, 1997, by and between the Company and the Rights Agent.

     On January 17, 1997, the Board of Directors of the Company declared a
dividend distribution of one Right for each outstanding share of the Company's
common stock, $0.01 par value (the "Common Stock"), to stockholders of record at
the close of business on January 27, 1997. Each Right entitles the registered
holder to purchase from the Company one one-thousandth (1/1,000) of a share of
Series A Preferred Stock, par value $0.01 per share (the "Preferred Stock"), at
a Purchase Price of $200 per one one-thousandth (1/1,000) of a share, subject to
adjustment. The description and terms of the Rights are set forth in a Rights
Agreement between the Company and the Rights Agent.

     Initially, the Rights will be attached to all Common Stock certificates
representing shares then outstanding, and no separate Rights Certificates will
be distributed. The Rights will separate from the Common Stock upon the earlier
of (i) the date of a public announcement by the Company that a person or group
of affiliated or associated persons (an "Acquiring Person") has acquired, or
obtained the right to acquire, beneficial ownership of twenty percent (20%) or
more of the outstanding shares of Common Stock (the "Stock Acquisition Date"),
or (ii) ten (10) business days (or such later date as the Board of Directors
shall determine) following the commencement of a tender or exchange offer that
would result in a person or group beneficially owning twenty percent (20%) or
more of such outstanding shares of Common Stock. The date the Rights separate is
referred to as the "Distribution Date."

     Until the Distribution Date, (i) the Rights will be evidenced by the Common
Stock certificates and will be transferred only with such Common Stock
certificates, (ii) new Common Stock certificates issued after January 27, 1997
will contain a notation incorporating the Rights Agreement by reference, and
(iii) the surrender for transfer of any certificates for Common Stock
outstanding will also constitute the transfer of the Rights associated with the
Common Stock represented by such certificates.

     The Rights are not exercisable until the Distribution Date and will expire
at the close of business on January 27, 2007, unless earlier redeemed by the
Company as described below.

     As soon as practicable after the Distribution Date, Rights Certificates
will be mailed to holders of record of the Common Stock as of the close of
business on the Distribution Date and, thereafter, the separate Rights
Certificates will represent the Rights. Except in connection with shares of
Common Stock issued or sold pursuant to the exercise of stock options or under
any employee plan or arrangements, or upon the exercise, conversion or exchange
of securities hereinafter issued by the Company, or as otherwise determined by
the Board of Directors, only shares of Common Stock issued prior to the
Distribution Date will be issued with Rights. In the event that (i) the Company
is the surviving corporation in a merger or other business combination with an
Acquiring Person (or any associate or affiliate thereof) and its Common Stock
remains outstanding





and unchanged, (ii) any person shall acquire beneficial ownership of more than
twenty percent (20%) of the outstanding shares of Common Stock (except pursuant
to certain consolidations or mergers involving the Company or sales or transfers
of the combined assets, cash flow or earning power of the Company and its
subsidiaries), or (iii) there occurs a reclassification of securities, a
recapitalization of the Company or any of certain business combinations or other
transactions (other than certain consolidations and mergers involving the
Company and sales or transfers of the combined assets, cash flow or earning
power of the Company and its subsidiaries) involving the Company or any of its
subsidiaries which has the effect of increasing by more than one percent (1%)
the proportionate share of any class of the outstanding equity securities of the
Company or any of its subsidiaries beneficially owned by an Acquiring Person (or
any associate or affiliate thereof), each holder of a Right (other than the
Acquiring Person and certain related parties) will thereafter have the right to
receive, upon exercise, Common Stock (or, in certain circumstances, cash,
property or other securities of the Company) having a value equal to two times
the Purchase Price of the Right. Notwithstanding any of the foregoing, following
the occurrence of any of the events described in this paragraph, all Rights that
are, or (under certain circumstances specified in the Rights Agreement) were,
beneficially owned by any Acquiring Person will be null and void.

     In the event that, at any time following the Stock Acquisition Date, (i)
the Company shall enter into a merger or other business combination transaction
in which the Company is not the surviving corporation, (ii) the Company is the
surviving corporation in a consolidation, merger or similar transaction pursuant
to which all or part of the outstanding shares of Common Stock are changed into
or exchanged for stock or other securities of any other person or cash or any
other property or (iii) more than 50% of the combined assets, cash flow or
earning power of the Company and its subsidiaries is sold or transferred (in
each case other than certain consolidations with, mergers with and into, or
sales of assets, cash flow or earning power by or to subsidiaries of the Company
as specified in the Rights Agreement), each holder of a Right (except Rights
which previously have been voided as set forth above) shall thereafter have the
right to receive, upon exercise, common stock of the acquiring company having a
value equal to two times the Purchase Price of the Right. The events described
in this paragraph and in the preceding paragraph are referred to as the
"Triggering Events."

     The Purchase Price payable, the number and kind of shares covered by each
Right and the number of Rights outstanding are subject to adjustment from time
to time to prevent dilution (i) in the event of a stock dividend on, or a
subdivision, combination or reclassification of, the Preferred Stock, (ii) if
holders of the Preferred Stock are granted certain rights, options or warrants
to subscribe for Preferred Stock or securities convertible into Preferred Stock
at less than the current market price of the Preferred Stock, or (iii) upon the
distribution to holders of the Preferred Stock of evidences of indebtedness,
cash (excluding regular quarterly cash dividends), assets (other than dividends
payable in Preferred Stock) or subscription rights or warrants (other than those
referred to in (ii) immediately above).

     With certain exceptions, no adjustment in the Purchase Price will be
required until cumulative adjustments amount to at least one percent (1%) of the
Purchase Price. No fractional shares of Preferred Stock are required to be
issued (other than fractions which are integral multiples of one one-thousandth
(1/1,000) of a share of Preferred Stock) and, in lieu thereof, the Company may
make an adjustment in cash based on the market price of the Preferred Stock on
the trading date immediately prior to the date of exercise.



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     At any time after any person or group becomes an Acquiring Person and prior
to the acquisition by such person or group of fifty percent (50%) or more of the
outstanding shares of Common Stock, the Board of Directors of the Company may,
without payment of the Purchase Price by the holder, exchange the Rights (other
than Rights owned by such person or group, which will become void), in whole or
in part, for shares of Common Stock at an exchange ratio of one-half (1/2) the
number of shares of Common Stock (or in certain circumstances, Preferred Stock)
for which a Right is exercisable immediately prior to the time of the Company's
decision to exchange the Rights (subject to adjustment).

     At any time following the Stock Acquisition Date, the Company may redeem
the Rights in whole, but not in part, at a price of $0.001 per Right (payable in
cash, shares of Common Stock or other consideration deemed appropriate by the
Board of Directors). Immediately upon the action of the Board of Directors
ordering redemption of the Rights, the Rights will terminate and the only right
of the holders of Rights will be to receive the $0.001 redemption price.

     The term "Disinterested Director" means any member of the Board of
Directors of the Company who was a member of the Board prior to the date of the
Rights Agreement, and any person who is subsequently elected to the Board if
such person is recommended or approved by a majority of the Disinterested
Directors, but shall not include an Acquiring Person, or an affiliate or
associate of an Acquiring Person, or any representative of the foregoing
entities.

     Until a Right is exercised, the holder thereof, as such, will have no
rights as a stockholder of the Company, including, without limitation, the
right to vote or to receive dividends. While it is expected that under current
federal income tax law, the distribution of the Rights will not be taxable to
stockholders or to the Company, stockholders may, depending upon the
circumstances, recognize taxable income in the event that the Rights become
exercisable for Common Stock (or other consideration) of the Company or for
common stock of an acquiring company as set forth above or in the event that the
Rights are redeemed.

     Other than those provisions relating to the principal economic terms of the
Rights, any of the provisions of the Rights Agreement may be amended by the
Board of Directors of the Company prior to the Distribution Date; PROVIDED, that
any amendments after the Stock Acquisition Date must be approved by a majority
of the Disinterested Directors. After the Distribution Date, the provisions of
the Rights Agreement may be amended by the Board in order to cure any ambiguity,
inconsistency or defect, to make changes which do not adversely affect the
interest of holders of Rights (excluding the interest of any Acquiring Person)
or to shorten or lengthen any time period under the Rights Agreement; PROVIDED,
HOWEVER, that no amendment to adjust the time period governing redemption shall
be made at such time as the Rights are not redeemable.

     A copy of the Rights Agreement has been filed with the Securities and
Exchange Commission as an Exhibit to a Registration Statement on Form 8-A filed
on January 27, 1997. A copy of the Rights Agreement is available free of charge
from the Rights Agent. This summary description of the Rights does not purport
to be complete and is qualified in its entirety by reference to the Rights
Agreement, which is incorporated herein by reference.



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     Amendment No. 1 provides that notwithstanding any provision to the contrary
contained in the Rights Agreement, neither SCF-IV, L.P., a Delaware limited
partnership ("SCF-IV"), nor any of its affiliates shall be deemed to be an
Acquiring Person as a result of any combination of the following actions: (i)
the execution and delivery of the Purchase Agreement, dated as of April 21,
1999, by and between the Company and SCF-IV (the "Purchase Agreement"); (ii) the
acquisition of shares of the Company's Series B Preferred Stock, $0.01 par value
per share (the "Series B Preferred Stock"), and/or the Company's Series C
Preferred Stock, $0.01 par value per share (the "Series C Preferred Stock"), in
accordance with the terms of the Purchase Agreement; (iii) the acquisition of
shares of Common Stock of the Company upon conversion of the shares of Series B
Preferred Stock or Series C Preferred Stock; (iv) the acquisition of securities
of the Company in accordance with the Purchase Agreement (including any Common
Stock issuable upon conversion, exercise or exchange thereof); or (v) an
acquisition of additional shares of Common Stock of the Company to the extent
permitted by the terms of the Purchase Agreement.

     In addition, Amendment No. 1 provides that in no event shall a Stock
Acquisition Date or a Distribution Date (both as defined under the Rights
Agreement) be deemed to occur as a result of (i) the execution and delivery of
the Purchase Agreement by SCF-IV and the Company, (ii) the acquisition by
SCF-IV of shares of Series B Preferred Stock and/or Series C Preferred Stock of
the Company in accordance with the terms of the Purchase Agreement, (iii) the
acquisition by SCF-IV of shares of Common Stock of the Company upon conversion
of the shares of Series B Preferred Stock or Series C Preferred Stock, (iv) the
acquisition by SCF-IV of securities of the Company in accordance with the terms
of the Purchase Agreement (including any Common Stock issuable upon conversion,
exercise or exchange thereof), or (v) the acquisition by SCF-IV of additional
shares of Common Stock of the Company to the extent permitted by the terms of
the Purchase Agreement. Amendment No. 1 further amends the Rights Agreement to
include several definitions.

     The Company has agreed that it will not further amend the Rights Agreement
or adopt any similar agreement, that conflicts with, or restricts SCF-IV to a
greater extent than the provisions contained in the Purchase Agreement.



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