Inertia Dynamics S-4 Registration of securities issued in business combination transactions

Exhibit 5.1

[Holland & Knight LLP Letterhead]

February 2, 2010

Altra Holdings, Inc.
and the Guarantors listed on Schedule I hereto
300 Granite Street, Suite 201
Braintree, Massachusetts 02184

     Re: Exchange by Altra Holdings, Inc. of $210,000,000 8⅛% Senior Secured Notes due 2016

Ladies and Gentlemen:

          We have acted as counsel to Altra Holdings, Inc., a Delaware corporation (the “Company”), the guarantors listed on Schedule I hereto organized under the laws of the State of Delaware (the “Delaware Guarantors”), and the guarantors listed on Schedule I hereto not organized under the laws of the State of Delaware (the “Non-Delaware Guarantors” and together with the Delaware Guarantors, the “Guarantors”), in connection with the Registration Statement on Form S-4 (the “Registration Statement”), filed by the Company with the Securities and Exchange Commission (the “Commission”) under the Securities Act of 1933, as amended (the “Securities Act”), relating to the issuance by the Company of up to $210,000,000 aggregate principal amount of 8⅛% Senior Secured Notes due 2016 (the “Registered Notes”). The Registered Notes are being issued pursuant to an indenture dated as of November 25, 2009 (the “Indenture”), by and among the Company, the Guarantors, and The Bank of New York Mellon Trust Company, N.A. as trustee (the “Trustee”). The Registered Notes will be offered by the Company in exchange for a like aggregate principal amount of its outstanding 8⅛% Senior Secured Notes due 2016. The Registered Notes are to be unconditionally guaranteed on a senior secured basis by each of the Guarantors pursuant to guarantees contained in the Indenture (the “Guarantees”).

     We have examined instruments, documents and records which we deemed relevant and necessary for the basis of our opinion hereinafter expressed. In such examination, we have assumed (a) the authenticity of original documents and the genuineness of all signatures, (b) the conformity to the originals of all documents submitted to us as copies, (c) the truth, accuracy and completeness of the information, representations and warranties contained in the records, documents, instruments and certificates we have reviewed and that there has been no undisclosed waiver of any right, remedy or provision contained in any such documents, and (d) that each transaction complies with all tests of good faith, fairness and conscionability required by law.

     We have also assumed (i) the valid existence and good standing of each Non-Delaware Guarantor and the Trustee, (ii) that each Non-Delaware Guarantor and the Trustee has the requisite limited liability company or corporate power and authority to enter into and perform its obligations under the Indenture and that the Indenture is the valid and legally binding obligation of each Non-Delaware Guarantor and the Trustee, and (iii) the due authorization, execution and delivery by each Non-Delaware Guarantor of its respective Guarantee. In addition, we have assumed that the Registered Notes and each Guarantee will be executed and delivered by an authorized officer of the Company or respective Guarantor, as the case may be, substantially in the form examined by us.

     Based on such examination and subject to the foregoing exceptions, qualifications, and limitations, we are of the opinion that:

     1. When the Registered Notes have been duly completed, executed, authenticated and delivered in accordance with the Indenture upon the exchange, the Registered Notes will be legal, valid and binding obligations of the Company enforceable against the Company in accordance with their terms, subject to the limitations of bankruptcy, insolvency, reorganization, moratorium or other laws or judicial decisions affecting the enforcement of creditors’ rights generally and general principles of equity.

     2. The execution, delivery and performance by each Delaware Guarantor of its Guarantee of the Registered Notes have been duly authorized by all necessary corporate or limited liability company action, as applicable, on the part of such Delaware Guarantor. The Guarantees of each of the Delaware Guarantors, when duly and validly executed and delivered by or on behalf of the Delaware Guarantors in accordance with the terms of the Indenture and as contemplated by the Registration Statement, and duly authenticated by the Trustee, will constitute the legal, valid and binding obligation of such Delaware Guarantor, enforceable against such Delaware Guarantor in accordance with its terms, subject to the limitations of bankruptcy, insolvency, reorganization, moratorium or other laws or judicial decisions affecting the enforcement of creditors’ rights generally and general principles of equity.

     This opinion speaks only as of its date. We undertake no obligation to advise the addressees (or any other third party) of changes in law or fact that occur after the date hereof, even though the change may affect the legal analysis, a legal conclusion or an informational confirmation in the opinion.

     We hereby consent to the filing of this opinion as an exhibit to the above-referenced Registration Statement and the use of our name wherever it appears in the Registration Statement, the prospectus and in any amendment or supplement thereto. In giving such consent, we do not thereby admit that we are included within the category of persons whose consent is required under Section 7 of the Securities Act or the rules and regulations of the Commission issued thereunder.

Very truly yours,
 

/s/ HOLLAND & KNIGHT LLP  

HOLLAND & KNIGHT LLP 

SCHEDULE I

GUARANTOR	JURISDICTION OF INCORPORATION
Altra Industrial Motion, Inc.		Delaware
American Enterprises MPT Corp.		Delaware
American Enterprises MPT Holdings, LLC		Delaware
Ameridrives International, LLC		Delaware
Boston Gear LLC		Delaware
Formsprag LLC		Delaware
Inertia Dynamics, LLC		Delaware
Kilian Manufacturing Corporation		Delaware
Nuttall Gear LLC		Delaware
TB Wood’s Corporation		Delaware
TB Wood’s Enterprises, Inc.		Delaware
TB Wood’s Incorporated		Pennsylvania
Warner Electric International Holding, Inc.		Delaware
Warner Electric LLC		Delaware
Warner Electric Technology LLC		Delaware