Specifications: Communication Level: Mono Receiving Frequency : 88~108MHz Transmission Frequency: F1: 85.5MHz / F2: 86MHz Frequency Response: 20~20,000Hz Sensitivity(S.P.L): 105dB?dB/mW(at 1KHz) Power supply: - Headphone: DC 3V (2x1.5V AAA batteries) - Transmitter: DC 3V (2x1.5V AAA batteries) Signal/Noise Ratio: >60dB Maximum operation distance: 30m, 360? Features: 1. RF/VHF wireless headphone. 2. FM radio receiver with auto-scan function. 3. Wired headphone for online chat. 4. Two independent transmitting bands to avoid interference. 5. Headphone can receive signals from transmitter in all directions even through barriers sush as doors, walls and glass etc.