Specification:  Name: 2.0 channel 100WX2 stereo BT audio power amplifier.  Adaptive power supply: DC9-24V/4A (Do not connect to AC).  BT version: 5.1.  Audio input: BT+AUX+USB+USB sound card.  Audio output: Left channel 100W+right channel 100W.  Volume adjustment: Classic mechanical knob (with volume scale), stepless adjustment.  Switch machine: Classic mechanical switch, one turn on and off, without long press and wait.  Adaptive speaker: 20-100W, 4-8ohm.  Protection mechanism: Overheating, overcurrent, short circuit, anti-static protection.  Product weight: Net weight 50g, Weight with package 85g.  Characteristic function: Support Wuzhi Audio APP. Modify Bluetooth name, password setting, prompt tone volume adjustment, on/off prompt tone, lullaby, sound effect selection + custom sound effect, USB flash disk playlist.  Size: 78*50*20mm.  Note:  It is recommended to equip with 8?? speaker and power supply of 9-24vdc. Overpressure is not allowed.  If the 4ohm speaker is driven, the power supply shall not exceed 12V.  Package includes:  1 x 2.0 channel 100WX2 stereo BT audio power amplifier