USB: to U disk (maximum support 32GB) TF: to TF memory card (maximum support 32GB) AUX: Audio Input Interface VOL-: Short press is the last song; Long press is the volume reduction. PLAY/PAUSE: Short press is the switch between pause and playback; Long press is the radio automatic station. VOL+: Short press is to the song; Long press is to increase the volume. MODE: Switchover of USB/TF//LINE IN/BLUETOOTH Voice Main control IC: AC5322B Bluetooth IC: AC5322B Bluetooth version is version 5.0 Music : MP3/WMA/WAV/FLAC/APE lossless music : 2 * 3W, connected to two 3W speakers Radio Frequency: 87.5-107.5 MHZ Introduction of Support Functions: Support MP3/USB/TF/LINE IN//BLUETOOTH/Remote Control/DC 5V About structure: panel size: 107 * 25 MM, panel corner and screw hole position, then cover surface, the depth of the board is 32 MM Description of recording function 1. Press the MODE button for a long time to recording, and then press the MODE button for a long time to cancel recording function. 2. Press the PLAY/PAUSE key to play the recording file. 3. When recording, it is more necessary to a device, such as a U disk or a TF card. Colour: Black material: plastic Package Contents: 1 * Bluetooth 5.0 DC 5V Amplifier Decoder Board 4 * Cable 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.