Pro Intercom HH10BR Handset with Active Cradle - RedPerformance: These U. S. made handsets are identical to those used on coin telephones, with transducers suitable for intercom use. To prevent feedback and permit high levels, the interior of the handset is partially filled with a dense mastic material, blocking acoustic coupling between the microphone and the earspeaker. A high quality shielded coil cord is then fitted. The HH10 A consists of the handset with push to talk switch, equipped with a coil