4 in 1 high frequence wireless headphone 1. The transmitter transmit stereo signal in 86 mhz to wireless headphone in the scope of 20 meters with interference free. 2. While the single headphone operating, it becomes fm radio receiver between 83.5-108mhz. 3. Connect headphone to computer with attached cable as for net icq purpose. 4. Inspecting the voice around transmitter in scope of 5 meter to receiver as an inspector.