Shop name:Chong Qing Shuo Yue Ke Ji You Xian Gong Si Product Name: Bluetooth Digital Amplifier Board Product : XH-A150 Chip : PAM8403 Transmission distance: up to 20 meters (no blocking) Supply voltage: 5V (-input) Color: green material: metal Number of channels: 2 Maximum : 5W+5W Product net weight: 42g Product size: 102*69*24mm Instructions for : 1. Install the TR18650 battery first, pay attention to the positive and negative points! (Battery is purchased by yourself) 2. Two wire link audio speakers, red is positive, black is negative 3. Insert an SD card with song files in the SD card slot or a USB flash drive with song files inserted in the USB interface. 4. Open the open key, it will automatically read your SD card or USB flash drive, and playing songs. If the SD card and USB flash drive are installed at the time, it will read the SD card file and by default. Package Contents: 1* Amplifier Board Only the above package content, other products are not included. Note: Light and different displays may the color of the item in the a little different from the real thing. The measurement allowed error is +/- 1-3cm.