The optional fully integrated COMMANDMICIII. Full control 2nd station capability. The IC-HM162 is a remote control for the IC-M504/604 that may be positioned up to 18.3m (60ft) away from the IC-M504/604. All M504/604 functions, including distress call, DSC, and foghorn, are available. The COMMANDMICIII may also be used as an intercom with the IC-M504/604. Multi function "Jog" dial Other features * Full dot-matrix LCD with 7-step dimmer setting * 2.8W (typical) external speaker terminal * Submersible PLUS (1.5m depth for 30 minutes)* Extra large 45mm (d) speaker for superior audio Color Black This waterproof remote microphone ONLY operates with the IC-M504