Sennheiser E 835-S Live Vocal Microphone with On Off Switch - 3-Pack

Consumer Alert: Most users do not need a license to operate this wireless microphone system. Nevertheless, operating this microphone system without a license is subject to certain restrictions: the system may not cause harmful interference; it must operate at a low power level (not in excess of 50 milliwatts); and it has no protection from interference received from any other device.