Features:  1. 5V power supply (powered by mobile phone chargers, computer UB ports, etc.), or directly powered by 4.2V lithium batteries, which can be directly charged.  2. Dual 3-watt stereo power amplifier output (BTL output, can not be connected to other power amplifiers without a common ground wire).  3. Multi-function: Bluetooth receive hands-free calls, forward and fast rewind, card MP3 playback, AU function, radio function comes with Bluetooth audio receiving module, after the mobile phone and Bluetooth module are paired and connected, the mobile phone can play MP3 or lossless APE files through Bluetooth and send to this The product's Bluetooth receiver module plays, which greatly facilitates the function and entertainment of the product. It also supports Bluetooth call function, which can realize hands-free mobile phone call, which has higher use value. This product can also play MP3 files in U disk or SD card, as well as radio playback, just like ordinary MP3 decoder boards.  4. Lithium battery model: BL-5C polymer 3.7v lithium battery(lithium battery not included), when charging the lithium battery of this machine, a 4.2v dedicated charger must be used, otherwise the battery will be damaged.  5. Manual: Click here.    Package included:  1 x YD-BT001 DIY Wireless Bluetooth Audio Electronic Kit with shell