Pryme SPM-332EB Quick Disconnect Responder Earpiece Mic for Vertex 700 800 900 (See List). Compatible with VX-820, VX-821, VX-824, VX-829, VX-871, VX-874, VX-879, VX-920, VX-921, VX-924, VX-929, VX-971, VX-974, VX-979, VX-P820, VX-P920, and VXD-720. The SPM-300EB RESPONDER is a medium-duty lapel microphone with a soft earhook-style earphone. The combination microphone-PTT features a 360 degree rotating clothing clip that can be used to secure the microphone to the user's shirt. Low profile, rugged lapel mic and in-line earphone. Soft earhook holds earphone in place during strenuous activity and is extremely comfortable to wear. High quality speaker and mic elements that allow for clear audio on both transmit and receive. Rugged, polycarbonate housing for maximum durability. Polyurethane-jacketed, coiled mic cable. Conveniently located Push-To-Talk button for easy use.