Voice opererated relays are often used in 'hands free' communication such as mobile radios, amateur tranceivers as well as some PA applications. The idea, of course is that instead of pushing a button on the microphone to talk, the sound of the voice activates it instead. This tiny kit measures approx 50 x 50 x 15mm and is designed to fit into the tightest spaces, has almost no turn-on delay, and has 3 second release time. 12VDC @ 35mA required. Kit is supplied with PCB electret mic, and all specified components.