Specifications: Communication Level: Mono Frequency Range: 85~108MHz 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: >50dB Maximum operation distance: 20m, 360? Features: 1. RF/VHF wireless headphone. 2. FM radio receiver with auto-scan function. 3. Headphone can receive signals from transmitter in all directions even through barriers sush as doors, walls and glass etc.