1. Power supply: You can directly use the MICRO-USB Android cable 5V for direct power supply, or you can also connect 5V power supply or 3.7V lithium battery (as shown below). Note that the 5V and 3.7V power supply interfaces are different. The 5V voltage is connected to 5V and GND, and the 3.7V lithium battery is connected to VBAT and GND. The maximum operating current is 5V2A. It is recommended to use a regulated 5V2A power supply for better sound quality. 2. Support USB sound card, free drive (plug and play). Connect the module to the computer with a USB cable, and the computer can play music through the module amplifier output. Audio output: output left and right stereo audio signals, which can be connected to two 2-8 ohm, 3-5W speakers, and 4 Euro 5W speakers. 3. This product has its own dual 5W power amplifier circuit, and must not be connected to another amplifier! The outputs of the two amplifiers may not be connected in parallel or the negative poles may be connected together, otherwise the power amplifier chip may be . 4. This product M38 is a low-power Bluetooth design solution, supports the Bluetooth 4.2 transmission, 2-channel stereo lossless playback, and the module can be connected to Bluetooth to quickly realize Bluetooth wireless transmission, which is very convenient. 5. In an open environment, the Bluetooth connection distance can reach 20 meters. Widely used in a variety of Bluetooth audio reception, a variety of audio DIY modification. Function Description: Bluetooth V4.2 version, support Bluetooth automatic connection technology, support WAV/WMA/FLAC/APE/MP3 lossless decoding, stereo dual channel output. After the module is powered on, the mobile phone searches for the Bluetooth name MH-M38, and can play music after connecting Bluetooth. Module blue indicator light: When the Bluetooth is n