SUMMARY

          The following summary highlights information contained elsewhere in this prospectus and is qualified in its entirety by the more detailed information and consolidated financial statements included elsewhere in this prospectus. This summary is not complete and may not contain all of the information that may be important to you. You should read the entire prospectus, including the “Risk Factors” section and our consolidated financial statements and notes to those statements, before making an investment decision. In this prospectus, unless indicated otherwise, references to (i) the terms “the company,” “we,” “us” and “our” refer to Altra Holdings, Inc. and its subsidiaries, (ii) the terms “pro forma” or “on a pro forma basis,” when used to describe our operations, unless the context otherwise requires, refer to our operations after giving effect to the Other Transactions and the Hay Hall Acquisition after conversion into U.S. dollars at the assumed exchange rates described herein (each as defined under “Our Formation, Recent Acquisitions and The Kilian Transactions”), as if they had occurred as of the applicable date for balance sheet purposes and the first day of the applicable period for results of operations purposes, (iii) any “fiscal” year refers to the twelve months ended on December 31 of such year, and (iv) “PTH,” “Colfax PT” or “Predecessor” refers to the power transmission business of Colfax Corporation, or Colfax, which is our accounting predecessor. For the definition of “EBITDA,” a reconciliation of EBITDA to a generally accepted accounting principle, or GAAP, measure, and information about the limitation of the use of these financial measures, see Note 3 in the Summary Consolidated Financial Data and Note 1 in the Selected Historical Financial and Other Data.

Our Company

          We are a leading global designer, producer and marketer of a wide range of mechanical power transmission, or MPT, and motion control products serving customers in a diverse group of industries, including energy, general industrial, material handling, mining, transportation and turf and garden. Our product portfolio includes industrial clutches and brakes, enclosed gear drives, open gearing, couplings, engineered bearing assemblies, linear components and other related products. Our products are used in a wide variety of high-volume manufacturing processes, where the reliability and accuracy of our products are critical in both avoiding costly down time and enhancing the overall efficiency of manufacturing operations. Our products are also used in non-manufacturing applications where product quality and reliability are especially critical, such as clutches and brakes for elevators, and residential and commercial lawnmowers. For the nine months ended September 29, 2006, we had net sales of $347.5 million, net income of $10.7 million and EBITDA of $46.9 million.

          We market our products under well recognized and established brands, many of which have been in existence for over 50 years. We believe many of our brands, when taken together with our brands in the same product category, achieved the number one or number two position in terms of consolidated market share and brand awareness in their respective product categories. Our products are either incorporated into products sold by original equipment manufacturers, or OEMs, sold to end users directly or sold through industrial distributors.

          We are led by a highly experienced management team that has established a proven track record of execution, successfully completing and integrating major strategic acquisitions and delivering significant growth in both revenue and profits. We employ a comprehensive business process called the Altra Business System, or ABS, which focuses on eliminating inefficiencies from every business process to improve quality, delivery and cost.

Our Industry

          Based on industry data supplied by Penton Information Services, we estimate that industrial power transmission products generated sales in the United States of approximately $30.3 billion in 2005. These products are used to generate, transmit, control and transform mechanical energy. The industrial power transmission industry can be divided into three areas: MPT products; motors and generators; and

adjustable speed drives. We compete primarily in the MPT area which, based on industry data, we estimate was a $15.7 billion market in the United States in 2005.

          The global MPT market is highly fragmented, with over 1,000 small manufacturers. While smaller companies tend to focus on regional niche markets with narrow product lines, larger companies that generate annual sales of over $100 million generally offer a much broader range of products and have global capabilities. The industry’s customer base is broadly diversified across many sectors of the economy and typically places a premium on factors such as quality, reliability, availability and design and application engineering support. We believe the most successful industry participants are those that leverage their distribution network, their products’ reputations for quality and reliability and their service and technical support capabilities to maintain attractive margins on products and gain market share.

Our Strengths

          Leading Market Shares and Brand Names. We believe we hold the number one or number two market position in key products across several of our core platforms. We are one of the leading manufacturers of industrial clutches and brakes in the world. We believe that over 50% of our sales are derived from products where we hold the number one or number two share and brand recognition, on a consolidated basis with our brands in the same product category, in the markets we serve.

          Large Installed Base Supporting Aftermarket Sales. With a history dating back to 1877 with the formation of Boston Gear, we believe we benefit from one of the largest installed customer bases in the industry which leads to significant aftermarket replacement demand creating a recurring revenue stream. For the nine months ended September 29, 2006, we estimate that approximately 43% of our revenues were derived from aftermarket sales.

          Diversified End-Markets. Our revenue base has balanced exposure across a diverse mix of end user industries, including energy, general industrial, material handling, mining, transportation and turf and garden, which helps mitigate the impact of business and economic cycles. In the first nine months of 2006, no single industry represented more than 10% of our total sales and in addition approximately 29% of our sales were from outside North America.

          Strong Relationships with Distributors and OEMs. We have over 700 direct OEM customers and enjoy established, long-term relationships with the leading MPT industrial distributors, critical factors that contribute to our high base of recurring aftermarket revenues. We sell our products through more than 3,000 distributor outlets worldwide.

          Experienced, High-Caliber Management Team. We are led by a highly experienced management team with over 425 years of cumulative industrial business experience and an average of 14 years with our companies. Our CEO, Michael Hurt, has over 39 years of experience in the MPT industry, while COO Carl Christenson has over 25 years of experience.

          The Altra Business System. We benefit from an established culture of lean management emphasizing quality, delivery and cost through the ABS. ABS is at the core of our performance-driven culture and drives both our strategic development and operational improvements. We estimate that in the period from January 1, 2005 through June 30, 2006, ABS has enabled us to achieve savings of over $5 million through various initiatives.

          Proven Product Development Capabilities. Our extensive application engineering know-how drives both new and repeat sales. Our broad portfolio of products, knowledge and expertise across various MPT applications allows us to provide our customers customized solutions to meet their specific needs.

Our Business Strategy

          We intend to continue to increase our sales through organic growth, expand our geographic reach and product offering through strategic acquisitions and improve our profitability through cost reduction initiatives. We seek to achieve these objectives through the following strategies:

Risks Related to Our Strategies

          You should also consider the many risks we face that could mitigate our competitive strengths and limit our ability to implement our business strategies, including:

          Investing in our common stock involves significant risks. Our ability to attain our objectives depends upon our success in addressing risks relating to our business and the industries we serve. You should carefully consider all of the information set forth in this prospectus, including the specific factors set forth under “Risk Factors,” before deciding whether to invest in our common stock.

Our Formation, Recent Acquisitions and Other Transactions

          The PTH Acquisition. On November 30, 2004, we acquired our original core business through the acquisition of Power Transmission Holding LLC, or PTH, from Warner Electric Holding, Inc., a wholly-owned subsidiary of Colfax Corporation, for $180.0 million in cash. PTH was organized in June 2004 to be the holding company for a group of companies comprising the power transmission business of Colfax Corporation. We refer to our acquisition of PTH as the “PTH Acquisition.”

          The Kilian Transactions. On October 22, 2004, The Kilian Company, or Kilian, a company formed at the direction of Genstar Capital LLC, or Genstar Capital, our principal equity sponsor, acquired Kilian Manufacturing Corporation from Timken U.S. Corporation for $8.8 million in cash and the assumption of $12.2 million of debt. At the completion of the PTH Acquisition, (i) all of the outstanding shares of Kilian capital stock were exchanged for approximately $8.8 million of shares of our capital stock and Kilian and its subsidiaries were transferred to our wholly owned subsidiary, Altra Industrial Motion, Inc., or Altra Industrial, and (ii) all outstanding debt of Kilian was retired with a portion of the proceeds of the sale of Altra Industrial’s 9.0% senior secured notes due 2011. See “Description of Indebtedness.”

          The Hay Hall Acquisition. On February 10, 2006, we acquired all of the outstanding share capital of Hay Hall Holdings Limited, or Hay Hall, for $50.3 million in cash. Hay Hall and its subsidiaries became our indirect wholly owned subsidiaries.

          In connection with our acquisition of Hay Hall, Altra Industrial issued £33.0 million of 11¹/4% senior notes due 2013. See “Description of Indebtedness.”

          The Bear Linear Acquisition. On May 18, 2006, Altra Industrial acquired substantially all of the assets of Bear Linear for $5.0 million in cash. Approximately $3.5 million was paid at closing and the remaining $1.5 million is payable over the next two and a half years. Bear Linear manufactures high value-added linear actuators for mobile off-highway and industrial applications.

Our Corporate Information

          We are a holding company and conduct our operations through Altra Industrial and its subsidiaries. We were incorporated in Delaware in 2004. Our principal executive offices are located at 14 Hayward Street, Quincy, Massachusetts 02171. Our telephone number is (617) 328-3300. Our website is located at www.altramotion.com. The information appearing on our website is not part of, and is not incorporated into, this prospectus.

Corporate Structure

We are Altra Industrial’s parent company and own 100% of Altra Industrial’s outstanding capital stock. Altra Industrial, directly or indirectly, owns 100% of the capital stock of its 44 subsidiaries. The following chart illustrates a summary of our corporate structure:

Our Principal Equity Sponsor

Genstar Capital, LLC, formed in 1988 and based in San Francisco, is a private equity firm that makes investments in high-quality, middle-market companies. Genstar Capital works in partnership with management as an advisor to us to create long-term value for our stockholders. Genstar Capital has over $900 million of committed capital under management and significant experience investing with a focus on life sciences, business services and industrial technology. Current portfolio companies include American Pacific Enterprises LLC, Andros Incorporated, AXIA Health Management LLC, Fort Dearborn Company, Harlan Sprague Dawley, Inc., INSTALLS inc, LLC, North American Construction Group, OnCURE Medical Corp., Panolam Industries International, Inc., PRA International, Inc. (NASDAQ: PRAI), Propex Inc. and Woods Equipment Company. Genstar Capital’s strategy is to make control-oriented investments and acquire companies with $100 million to $1 billion in annual revenues in a variety of growth, buyout, recapitalization and consolidation transactions.

Currently, Genstar Capital Partners III, L.P. and Stargen III, L.P., which are entities controlled by Genstar Capital, own 25,985,000 shares of our convertible preferred stock. Immediately prior to the consummation of our initial public offering, these shares will convert into 12,992,501 shares of our common stock, representing 65.8% of our issued and outstanding shares. Entities controlled by Genstar Capital will sell 4,997,998 shares of our common stock in this offering, plus an additional 935,803 shares of our common stock if the underwriters exercise their over-allotment option in full. Entities controlled by Genstar Capital will beneficially own 34.6% of our common stock after the offering, or 30.6% if the underwriters exercise their over-allotment option in full.

Trademarks

Warner Electric, Boston Gear, Kilian Manufacturing, Nuttall Gear, Ameridrives, Wichita Clutch, Formsprag Clutch, Bibby Transmissions, Stieber, Matrix International, Inertia Dynamics, Twiflex Limited, Industrial Clutch, Huco Dynatork, Marland Clutch, Delroyd Worm Gear, Bear Linear and Saftek are some of our proprietary brand names and trademarks that appear in this prospectus. All other trademarks appearing in this prospectus are the property of their respective holders.

The Offering

          The number of shares of our common stock outstanding after the offering excludes shares available for issuance under future option grants under our equity incentive plan but includes restricted shares of our common stock for which the restrictions have not yet lapsed based on employee service. Unless we indicate otherwise, all information in this prospectus assumes the underwriters do not exercise their option to purchase from the selling stockholders up to 1,500,000 shares of our common stock to cover over-allotments.

          Unless we indicate otherwise, all information in this prospectus assumes an initial public offering price of $15.00 per share, the midpoint of the estimated public offering price range set forth on the cover page of this prospectus. All reference to our common stock and per share amounts give effect to the two for one reverse stock split effected on December 11, 2006 and assumes the conversion of all of our outstanding preferred stock. Our preferred stock will automatically convert into shares of common stock on the effective date of this offering on a one share of common stock for every two shares of preferred stock outstanding basis.

Summary Consolidated Financial Data

          The following unaudited table is a reconciliation of our net income to EBITDA (in thousands):