Features: Bluetooth solution, better Bluetooth decoding effect, support for lossless decoding methods such as WMA FLAC APE, TWS true wireless box matching function, and remote firmware . Stereo volume and subwoofer volume can be adjusted separately, with a wide range of adjustment. The master volume knob has a key function, click to play to pause, double click to the song, triple click to select or cancel mode : -LT23 Function: 2.1 channel 50W+50W+100W, AUX+Bluetooth BT+U disk lossless decoding+USB sound card type:Amplifier board color:Black Material:plastic Package Contents: 1 x -LT23 Bluetooth 5.1 AUX Digital Amplifier board Only the above package content, other products are not included. Note: Light reflection 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.