D Debra PRO ST-102 UHF Stereo Wireless in Ear Monitor System,Wireless IEM with Bodypacks and Headsets,530-580Mhz Transmitter and Receiver,Ideal for Stage,Studio,Speech(1 Bodypack with Transmitter)

"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; and it has no protection from interference received from any other device."