The ONE-PTT dynamic microphone adds more versatility to your ONE 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 microphone stand, you can hang this microphone to the ONE 500 side for a fast and easy call. You can also fix it to any other surface following your preferences.