The Bifrost Gear COM-RAC for Comtac allows operators to easily convert their Sordin headsets to work with the Ops-Core AMP Helmet Rail Mount Kit (RAC Arms) Features: Converts OPS-Core AMP arms to work with Sordin Headsets and Earmuffs Allows headsets to attach to rear dovetails on ARC rails Installs in seconds, no modifications to OPS Core AMP arms or headsets required Compatible with the following headsets: MSA Sordin (over the head version) TCI Liberator (over the head version) TEA High Threat (over the head version) (Includes one pair of adapter brackets; OPS-Core AMP Helmet Rail Mount Kit and headset not included) US and International Patents Pending