Standard RAM4 Remote Access MicrophoneModel: SSM-70HFeatures:Controls all radio functions of the GX6000 and GX6500Operate up to 2 RAM4 wired remote stationsSubmersible IPX8 waterproof rating (1.5 M or 4.92 feet for 30 minutes)Intercom feature allows you to communicate between the radio, RAM4 and Wireless RAM4W microphonesFull AIS target displayPerform all DSC functions: Individual calling, group calling, Position polling and moreLarger high resolution easy to read display with bright backlightRotary channel and volume controlsProgrammable hot keys for quick menu access23 routing cable includedThe SSM-70H is only compatible with the GX1800, GX1850, GX2400 and GX6000, it is not backwards compatible with other Standard Horizon Models