The RE-2AS PTT dynamic microphone adds more versatility to your RE-2AS unit. This new device allows you to have a public announcement input right there at your fingertips. This Push To Talk microphone can be directly connected to the priority audio input to bypass the back ground music. As it is directly powered from the USB port inside the unit, you do not need to add an external power supply. With the included support, you can hang this microphone to the RE-2AS side for a fast and easy call.