Product name: 2.1 channel 50W+50W+100W subwoofer adjustment bluetooth audio amplifier : -LT23 amplifier chip: domestic chip Bluetooth version: 5.1 Bluetooth transmission distance: 10 meters. Audio input: Bluetooth+AUX+U disk+USB sound card. Audio output: left channel 50W + right channel 50W + subwoofer 100W Adapter supply: DC9-24V, greater than equal 5A (can not be connected to AC) Adapter speakers: left and right channels 10-50W, 4-8ohm; subwoofer 20-50W, 4-8ohm Volume adjustment: separate adjustment of master volume, stereo volume and subwoofer volume, wide adjustment range: master volume with buttons: single click: play/pause; double click: song; triple click: select or cancel box matching mode Protection mechanism: over temperature, over current, short circuit, anti-static protection Features: Support Wuzhi Audio app. Modify the bluetooth name, password setting, volume adjustment of prompt tone, on/off prompt tone, aid song, firmware upgrade, etc. box pairing function, the true wireless function enables two sets of speakers to be combined into left and right channel pairing boxes, with a sense of spatial positioning stronger. Product size: 75x70x20mm (for Wuzhi Audio APP download link: (This version of the APP is with new products, please download and the APP before using the product) http://.qingdaowuzhi.cn/btapp/Wuzhi_Audio_V1.0.3.apk Link to -LT23 product manual: http://.qingdaowuzhi.cn//lt23/lt23ins.pdf) Colour:black Material:PCB+Metal Package Contents: 1 x 2.1 channel audio amplifier board 1 x Screwdriver 1 x DC adapter 1 x DC cable 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.