Potentiometer adjustment: total volume, stereo bass, stereo treble, subwoofer volume, subwoofer frequency, total volume with buttons: click: play/pause; Double click: next song; Three clicks: select or cancel the box matching mode Protection mechanism: over temperature, over current, short circuit, anti-static protection Featured function: support Wuzhi Audio APP. Modify Bluetooth name, password settings, prompt tone volume adjustment, on/off prompt tone, lullaby, firmware upgrade, etc. The box to box function and the true wireless function enable the two sets of speakers to be combined into a left and right channel box to box, with a stronger sense of spatial positioning. Product name: 2.1 channel 160Wx2+220W potentiometer external Bluetooth audio amplifier Model: ZK-HT22 Power amplifier chip: TDA7498E Bluetooth version: 5.1 Bluetooth transmission distance: 10 meters (if you need a longer distance, please connect an external antenna) Audio input: Bluetooth+AUX+U disk+USB sound card Audio output: left channel 160W+right channel 160W+subwoofer 220W Adaptive power supply: DC15-36V, 9A (AC power is not allowed) Adaptive speaker: 30-200W, 4-8 for left and right channels; Subwoofer 30-200W, 4-8 External lead: 5 7P shielded wires 35cm Product size: 126 x 106 x 29mm Material: PCB+Metal colour: Black Package Contents: 1 x ZK-HT22 lead in Bluetooth amplifier module 5 x 7P shielded wire 5 x Potentiometer Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.