The Standard Horizon CMP-460 Speaker Mic is a submersible microphone that is compatible with HX320, HX460S, HX471S, HX370S, HX370SAS, HX500S, HX600S, HX500SBLI, HX750S, HX751L, HX850S, HX851L, HX890BK, and HX809NB hand held VHF radios.