Motorola speaker microphonePush-to-talk button on unit Volume dial on radio controls microphone volume Additional battery required Compatible with talkabout 270, 280, T289, T5100, T5200, T5300, T5320, T5400, T5410, T5420, T5600, T5620, T5700, T5710, T5720, T5800, T5820, T5950, T6200, T6210, T6220, T6250, T6300, T6310, T6320, T6400, T7200, fr50 and fr60 radiosMOT53724