Functions: One end is connected to the instrument's audio port and the other end is connected to the sound system, transmitting audio signals wirelessly. Equipped with a USB charging cable, two Micro USB plugs, the transmitter and receiver can be charged at the same time. There are four channels, up to four systems can be used simultaneously, the signals will not interfere with each other. Transmitter Indicator Light: When booting, the indicator light will indicate the channel number according to the corresponding channel flashing times. After that, the red light is still on while in transmitting state. Receiver indicator light: When booting, the indicator light will indicate the channel number according to the corresponding channel flashing times. Specifications: Material : plastic metal Black color Channel : 4 Frequency response : UHF System frequency response : 20Hz 20kHz Frequency : 730 MHz max. Transmission distortion : andlt 50m (unobstructed) Latency : andlt 4 ms Power supply : 3.7V or 600mAH built-in USB cable with lithium battery Charging time : andlt 2 hours Working hour : 4 6 hours (full charge) Size : Approx. 11 x 4.3 x 1.7cm or 4.30 x 1.68 x 0.66in Weight : approx. 269g Package list: 1 x Transmitter 1 x Receiver 1xusb charging cable 1xManual Due to the different production batches, the power switch has two modes (press up or press to open). Please be aware of: