Specificatioon: 1.Omnidirectional 2.Frequency:863.3-863.5MHz or 912.5-914.5MHz 3.Distortion:<0.5% 4.S/N:>50dB 5.Channel sepatation:>35dB 6.Effective Transmitting distance:up to 300feet(with no interference) 7.Headphones battery:700mA rechargeable NI-MH battery 8.Power supply of transmitter:DC 12V