Standard Horizon SSM-17H - Compact Speaker Microphone (replaces MH-57A4B)
Standard Horizon MH-57A4B - SSM-17H - Miniature speaker microphone with earphone jack Compatible with Standard Horizon marine VHF radio models, HX890E, HX870E, HX851E, HX760E, HX751E, HX407E. HX400E, HX370E, HX290E, HX210E and HX40E.