. . . EXHIBIT 21.1 SUBSIDIARIES OF ALTRA HOLDINGS, INC. JURISDICTION OF NAME OF SUBSIDIARY ORGANIZATION - - Altra Industrial Motion, Inc. Delaware - American Enterprises MPT Corp. Delaware - Nuttall Gear LLC Delaware - American Enterprises MPT Holdings, LLC Delaware - Ameridrives International, LLC Delaware - Formsprag LLC Delaware - Warner Electric LLC Delaware - Warner Electric Technology LLC Delaware - Boston Gear LLC Delaware - The Kilian Company Delaware - Kilian Manufacturing Corporation Delaware - 3091780 Nova Scotia Company Nova Scotia, Canada - Kilian Canada, ULC Nova Scotia, Canada - Warner Electric International Holding, Inc. Delaware - Warner Electric (Holding) SAS France - Warner Electric Europe SAS France - Warner Electric Group GmbH Germany - Warner Electric Verwaltungs GmbH Germany - Stieber GmbH Germany - Warner Electric (Netherlands) Holding, B.V. Netherlands - Warner Electric Australia Pty. Ltd. Australia - Warner Shui Hing Limited, (HK) Hong Kong - Warner Electric (Singapore), Ltd. Singapore - Warner Electric (Taiwan) Ltd. Taiwan - Warner Electric (Thailand) Ltd. Thailand - Warner Electric UK Group Ltd. United Kingdom - Warner Electric UK Holding, Ltd. United Kingdom - Wichita Company Ltd. United Kingdom - Hay Hall Holdings Limited United Kingdom - The Hay Hall Group Limited United Kingdom - Matrix International, Ltd. United Kingdom - Matrix International GmbH Germany - Inertia Dynamics, LLC Delaware - Bibby Group Ltd. United Kingdom - Bibby Transmissions Ltd. United Kingdom - Bibby Turboflex SA South Africa - Turboflex Ltd. United Kingdom - Torsiflex Ltd. United Kingdom - Rathi Turboflex Pty Ltd India - Huco Power Transmission, Ltd. United Kingdom - Huco Engineering Industries Ltd. United Kingdom - Dynatork Air Motors Ltd. United Kingdom - Dynatork, Ltd. United Kingdom - Twiflex Ltd. United Kingdom - Saftek Ltd. United Kingdom