Product name: 2.1 channel Bluetooth audio amplifier module Product model: ZK-HT21 3G Bluetooth version: 5.0 (unobstructed, 15 meters) Input method: AUX + Bluetooth + USB (wheel button to switch modes and songs) Number of channels: 2.1 channels (left channel + right channel + subwoofer) Power amplifier chip: TDA7498E Adaptable power supply: DC 15~36V (less than 9V undervoltage protection, also supports 12V power supply) Adaptable speaker: 30-200W, 4-8Ω Output power: left and right channels Less than 160W Subwoofer Less than 220W Protection mechanism: Anti-reverse connection, under-voltage, overheating, over-current, short-circuit protection Product weight: One-piece net weight 344g, including packaging 393g Net weight of lead-out potentiometer 270g, including packaging 337g Tip: Only when the audio signal input is large enough and the power supply voltage/current is large enough, will there be sufficient output power! The higher the power supply voltage, the greater the output power, and the smaller the speaker impedance, the greater the output power! Please make sure that the power of the adapted power supply is greater than the actual working power of the amplifier! Type: B: three generations of one Colour:Black Material:ABS Size:145x126x28mm Package Contents: 1x Bluetooth power amplifier module 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.