This multifunction microtransmitter is ideal for both phone and environment listening. In practice it enables you to intercept clearly the voices of both parties engaged in a telephone conversation, but when the phone isn't in use, ie, there are no calls in progress, it works as an environmental bug. The system is really small so very easy to hide. The sound moved, up to 600 meters away, is of excellent quality. The device allows the control of the amplification and the microphone cable length on request.