TheAVerMic AW315S contains a wireless microphone and a receiver in a packaging.With 2.4 GHz wireless technology noise and speaker buzz reduction this hands-free design not only gives teacher total freedom to interact with students it also delivers natural voice in great clarity and stability. The microphone (TX) will automatically search for the receiver (RX) and start to pair. Just power on the microphone and speaker and you do not need to worry about pairing and everything else. The AVerMic AW315 is built-in a ground loop noise isolator which can help to reduce the ground loop interference caused by a difference in ground potential and prevent EMI. More from the Manufacturer.