Product name: 2.1 channel Bluetooth audio amplifier module Material: PCB+metal Product model: YS-LT21 Bluetooth version: 5.1 Audio channel: 2.1 channel Color: Black Input mode: Bluetooth+AUX+USB+USB sound card Power supply: above DC9-24V/3A Audio output: left channel 15W+right channel 15W+subwoofer 30W Adaptive horn: 10W-50W/4 Ω - 8 Ω Output power: 15W x 2 (left and right channels)+30W (subwoofer) Volume adjustment: high-end encoder knob adjustment, smooth feel Protection mechanism: overheating, overcurrent, short circuit, anti-static protection Special function: support YS Audio APP control Product size: 75 x 60 x 22 mm Product weight: net weight 66g Note: It is recommended to equip an 8 Ω horn with power supply of 9-24V DC. Overvoltage is not allowed. If the 4 Ω horn is driven, the power supply cannot exceed 12V. Package Contents: 1 x YS-LT21 amplifier board 1 x DC adapter 1 x screwdriver