Carrier Frequency: 858MHz-870MHz, 6 pre-programmed frequency bands to select for steady audio frequency signal. The receiver enjoys the previous using memory function for accidentally resetting. The receiver utilizes the audio-tuning function. The transmitter will be automatically shut off if no audio signal comes. Automatically cut-off operation on the receiver before battery's deficiency ensures perfect operating. The transmitter serves as both storage cradle and battery charger for the headphones. It also assures the constant charging without damaging the batteries at the turn-off state. Frequency Control: PLL Synthesized Function Carrier Frequency: 858MHz-870MHz Modulation: FM Radiated Power: <10mW Max. Input Level: Virtual Value 500mV (1kHz sine wave) Transmitting Power Supply: DC 12V/300mA (Center Positive) Receiver Power Supply: 2 x LR03 (AAA) Ni-MH 1.2V 850mA Chargeable Batteries Frequency Response: 60Hz-15kHz S/N Ratio: >45dB (1kHz sine wave, A- weighted) Total Harmonic Distortion: less than1% Channel Separation: more than 30dB