For Bluetooth V4.2 version of Bluetooth automatic technology, support WAV/WMA/FLAC/APE/MP3 lossless decoding, two-channel stereo output After powering on the module, the phone searches for the name Bluetooth MH-M18 and can listen to music when connected to Bluetooth.M18: MUTE control terminal: used to control the power amplifier board. When muting, MUTE outputs 3.3V high level and outputs low level during playback. Power-off function volume: The default output is 100% volume. Press the button to control the volume up and down. If the control volume is less than 15%, the output volume will be 15% after power on; if control volumeIt is recommended to use a 5V2A regulated power supply for better sound quality.Support USB sound card, free drive (plug and play) Connect the module to the computer with the USB cable and the computer can play music through amplifier output Note: The data are all manual measurement, please allow 1-13cm error, due to the light and temperature difference. display, there will be some color difference, depending on the physical item received.