Filed by Cameron International Corporation

Commission File No. of Subject Company: 1-13844

Pursuant to Rule 425 under the Securities Act of 1933, as amended

Subject Company: NATCO Group, Inc.

Commission File No. of Subject Company: 001-15603

Disclaimers

Forward-Looking Statements

Information set forth in this document contains forward-looking statements, which involve a number of risks and uncertainties. Cameron
International Corporation (“Cameron”) and NATCO Group Inc. (“NATCO”) caution readers that any forward-looking information is not a guarantee
of future performance and that actual results could differ materially from those contained in the forward-looking information. Such forward-looking
statements include, but are not limited to, statements about the benefits of the business combination transaction involving Cameron and NATCO,
including future financial and operating results, the new company’s plans, objectives, expectations and intentions and other statements that are
not historical facts.

The following additional factors, among others, could cause actual results to differ from those set forth in the forward-looking statements: the
ability to satisfy the closing conditions of the transaction, including obtaining regulatory approvals for the transaction and the approval of the
merger agreement by the NATCO stockholders; the risk that the businesses will not be integrated successfully; the risk that the cost savings and
any other synergies from the transaction may not be fully realized or may take longer to realize than expected; disruption from the transaction
making it more difficult to maintain relationships with customers, employees or suppliers; the impact of other acquisitions that Cameron or NATCO
have made or may make before the transaction;competition and its effect on pricing; and exploration and development spending by E&P
operators. Additional factors that may affect future results are contained in Cameron’s and NATCO’s filings with the Securities and Exchange
Commission (“SEC”), which are available at the SEC’s web site http://www.sec.gov. Cameron and NATCO disclaim any obligation to update and
revise statements contained in these materials based on new information or otherwise.

Additional Information and Where to Find It

In connection with the proposed merger, Cameron will file with the Securities and Exchange Commission (the “SEC”) a Registration Statement on
Form S-4 and NATCO will file a proxy statement, which will be mailed to NATCO’s stockholders. INVESTORS AND SECURITY HOLDERS ARE
URGED TO CAREFULLY READ THE S-4 AND PROXY STATEMENT REGARDING THE PROPOSED MERGER WHEN THEY BECOME
AVAILABLE BECAUSE THEY WILL CONTAIN IMPORTANT INFORMATION. You may obtain a free copy of the S-4 and proxy statement (when
available) and other related documents filed by Cameron and NATCO with the SEC at the SEC’s website at www.sec.gov. The S-4 and proxy
statement (when it is available) and the other documents may also be obtained for free by accessing Cameron’s website at www.c-a-m.com under
the heading “Investor Relations” and then under the heading “SEC Filings” or by accessing NATCO’s website at www.natcogroup.com under the
tab “Investor Relations” and then under the heading “SEC Filings”.

Participants in the Solicitation

NATCO and its directors, executive officers and certain other members of management and employees may be soliciting proxies from its
stockholders in favor of the merger. Information regarding the persons who may, under the rules of the SEC, be considered participants in the
solicitation of the stockholders in connection with the proposed merger will be set forth in NATCO’s proxy statement when it is filed with the SEC.
You can find information about NATCO’s executive officers and directors in their definitive proxy statement filed with the SEC on March 23, 2009.
You can obtain free copies of these documents from NATCO using the contact information above.

Transaction Summary

vNATCO stockholders to receive 1.185 Cameron shares for each NATCO
share

vTransaction value: $780 million

vAll-stock, tax-free merger

vClosing conditions:

oRegulatory approvals, including HSR clearance

oApproval by NATCO’s stockholders

oNo financing conditions

vExpect to close in third quarter 2009

vPost-closing:

oCameron fully diluted shares outstanding to total approximately 244
million

oNATCO’s current shareholders to own approximately ten percent of
Cameron’s outstanding shares

vExpected to be accretive to 2010 earnings

vNATCO is a leading provider of separation and processing technology and solutions
for the worldwide oil and gas industry

oBroad product line of standard and engineered process separation equipment

oStrong brand name

oSeveral proprietary technologies, some of which could yield high-potential new
products

oMajority of revenues expected to be generated internationally

vNATCO generated $657 million of revenue and $74 million of pro forma segment
profit in 2008.

2008 Segment Profit1

Overview Of NATCO

54%

33%

13%

Integrated
Engineered
Solutions

$216

Integrated
Engineered
Solutions

$36

Automation &
Controls

$5

Automation &
Controls

$89

Standard &
Traditional

$353

Standard &
Traditional

$32

44%

49%

7%

1Excludes legal and compliance
review costs of $10.3 million

Strategic Rationale

vEnhances role as a leading provider of separation and processing technologies
and solutions

oComplementary engineered products and technologies

oProvides Cameron with Standard & Traditional product line

oLeverages proprietary gas separation technologies

vPotential for significant synergies ($30 to $40 million)

oPublic company costs and other administrative costs

oImproved facility utilization through insourcing products that other Cameron
businesses, particularly Petreco, currently outsource

oSupply chain efficiencies

oSelect office/facility consolidation

vCreates new growth opportunities

oLeverage Cameron’s larger international footprint

oCombine R&D efforts on new product development

oImproves Cameron’s capabilities for subsea processing of deepwater
production

oPotential for cross-selling of Cameron’s broader product line (valves,
compressors, wellheads, etc.)

Cameron’s 2008 Revenues (pro forma NATCO)

Exploration/Development/Production Transportation/Refining/LNG Industrial

Surface

Drilling

Flow
Control

Distributed

Process

é Surface

ê Subsea

Measurement

$500

million

$300
million

$100
million

Reciprocating

Centrifugal

Combined Processing
and Separation
business