Feature: 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 USB charging cable, two Micro USB plugs, transmitter and receiver can be charged at the same time. There are four channels, you can use up to four systems at the same time, the signals will not interfere with each other. Transmitter light indicator: During start-up, the indicator light will indicate the channel number according to the corresponding channel flashing times. Later, the red light continues to shine, being in the broadcasting state. Receiver indicator light: During start-up, the indicator light will indicate the channel number according to the corresponding channel flashing times. Specification: Material: plastic metal Colour black Channel: 4 Frequency Response: UHF System Frequency Response: 20 Hz 20 kHz Frequency: 730 MHz Memory clock speed Transmission Distortion: Delay: Power Supply: 3,7V/600mAH Built-in USB Cable With Lithium Battery Charging time: Working hour: 46 hours (full charge) Size: approx. 11 * 4,3 * 1,7 cm / 4,30 * 1,68 * 0,66 inch Weight: approx. 269 g List of packages: 1 * Transmitter 1 * receiver 1 * usb charging cable 1 * manual Note: Due to different production batches, the power switch has two modes (press up/press to open).