VOL-: Short press to select the previous song; long press to decrease the volume PLAY/PAUSE: Short press to switch between pause and play; long press to switch between USB, TF, FM, LINE IN, and BLUETOOTH; short press to automatically search channels in FM radio mode VOL+: Short press to select the next song; long press to increase the volume Equipped with Bluetooth calling function; power supply voltage is 5V, current requirement is above 2A Supports music formats: MP3, WMA, WAV, FLAC, APE (lossless format) ON/OFF: Power switch DC 5V: Charging interface Switch indicator light Built-in microphone for calling function USB port: Connects to U disk (supports up to 32GB) TF card slot: Connects to TF memory card (supports up to 32GB) Main control IC: AC6826A Bluetooth IC: AC6826A with Bluetooth 5.0 Output power: 2 x 3W; supports connection to two 3W speakers FM radio frequency range: 87.5 – 107.5 MHz Supported functions: MP3, USB, TF, LINE IN, FM, BLUETOOTH, DC 5V input Color: Black Material: ABS Package Contents: 1 x MP3 decoder board 1 x Audio cable Note: Lighting and monitor differences may cause slight variations in color between the image and the actual item. Measurement may vary by +/- 1-3 cm.