Product name: 2.1 channel 15W+15W+30W subwoofer adjustment bluetooth audio power amplifier Model: -LT22 Power amplifier chip: domestic chip Bluetooth version: 5.1 Bluetooth transmission distance: 10 .Audio input: Bluetooth+AUX+U disk+USB sound card. Audio output: left channel 15W + right channel 15W + subwoofer 30W Adapter power supply: DC9-24V, 3A (can not be connected to AC) Adapter speakers: left and right channels 10-30W, 4-8ohm; subwoofer 10-30W, 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. the bluetooth name, password setting, volume adjustment of prompt tone, on/off prompt tone, sleep 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 compatible with new , please download and the APP using the product) http://.qingdaowuzhi.cn/btapp/Wuzhi_Audio_V1.0.3.apk Link to -LT22 product manual: http://.qingdaowuzhi.cn//lt22/lt22ins.pdf) Colour:black Material:PCB+Metal Package Contents: 1 x 2.1 channel audio power amplifier board 1 x Screwdriver 1 x DC adapter 1 x DC cable Only the above package content, other are not included. Note: Light reflection and different displays may cause the color of the item in the a little different from the real thing. The measurement allowed error is +/- 1-3cm.