Yaesu Vertex Standard VC-24 Headset Microphone with VOX and PTT Yaesu STANDARD Horizon VC-24 VOX HEADSET. Fits Yaesu Models VX-6R, VX-7R, FT-270R, VX-170, FT-277R, VX-177. Fits Standard Horizon & Vertex Models HX-370S, HX-460S, HX-470S, HX-471S, HX-500S HX-600S, HX-750S,HX-850S, HX-760S, HX-751, HX-851, HX-290, HX-400