Effective working distance: 25m Frequency range: 640MHz~690MHz Frequency response:20HZ~18KHz Number of frequency points: 25 Audio dynamic range: 100dB Transmission parameters 0V working current: 140mA 3V operating current: 140mA 48V working current: 160mA Battery capacity: 500mA Transmit power: 12dBm Usage time: 3.5h Shutdown voltage: 3.3V Charging time: 2.5h Receive parameters Working current: 80mA Shutdown voltage: 3.3v Battery capacity: 500mA Usage time: 6h Charging time: 2.5h Receiving sensitivity: Less than -100dBm Distortion: Less than 0.5% Colour:Black Material:plastic Package Contents: 1 x receiver 1 x transmitter 1 x charging cable Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.