Functional Description: 1. Bluetooth V4.2 version supports Bluetooth auto-link technology, WAV/WMA/FLAC/APE/MP3 lossless decoding, stereo dual-channel output. 2. When the module is powered on, the mobile phone searches for the Bluetooth name HW-406, which can play music when connected to Bluetooth. 3. Modular blue indicator: When Bluetooth is not connected, the indicator fast flashes. When Bluetooth is connected, the indicator lights are always on. When Bluetooth is playing, the indicator lights slow flashes. 4. Power supply: It can be directly powered by 5V of MICRO USB Android line, or it can be connected to 5V power supply or 3.7V lithium battery. Note that 5V and 3.7V power supply interfaces are different. 5V is connected to 5V and GND, and 3.7V lithium battery is connected to VBAT and GND. The maximum working current is 5V2A. It is recommended to use 5V2A stable voltage power supply for better sound quality. 5. Support USB sound card, drive-free (Plug and Play). Connect the module with the computer by USB data line, and the computer can play music and output it through the module's power amplifier. 6. Audio Output: Output of left and right channel stereo audio signal, can be connected to two 2-8 ohm, 3-5W speakers respectively, 4 ohm 5W speakers for storage. 7. This product has its own dual 5W power amplifier circuit, it must not be used by another power amplifier! The output of two power amplifiers can not be connected in parallel or the negative poles can be connected together, otherwise the chip of power amplifier will be damaged