1. Adopting high-power digital power amplifier dedicated inductors, high current, low magnetic loss, low heat generation, and using oxygen free copper wires to improve sound quality; The magnetic shielding mechanism is resistant to electromagnetic interference. 2. TPA3221+TPA3221, lossless transmission, lossless decoding, no loss, perfectly displaying the dynamics and details of sound, without burrs at high frequencies, rounded at mid tones, powerful at low frequencies, and good elasticity. 3. Equipped with protection mechanism, input undervoltage, input anti reverse connection, overheating, overcurrent, and short circuit Product name: 2.1 channel BT amplifier board 100W+100W+200W Product model: -ST21 Adapted power supply: The working voltage range is 12-30VDC, and it is recommended to use a DC power supply with a voltage of 24V-28V and a current of 10A or above. Maximum power: Left or right channel - 105W@30V, 4ohm; 55W@30V , 8ohm. Subwoofer - 208W@30V 2ohm; 105W@30V, 4ohm. In short, the higher the voltage, the smaller the resistance, and the greater the output power. Adapted speakers: Left and right channels, supporting 3-8 ohms and speakers up to 100W; The subwoofer supports 2-8 ohms and speakers up to 200W. BT chip: 5.1, transmission distance of 15 meters. Input : BT+AUX+USB drive+sound card. Number of channels: 2.1, Left channel+right channel+subwoofer Power amplifier chip: Two TI TPA3221 Protection mechanism: Input undervoltage, input anti reverse connection, overheating, overcurrent, short circuit protection. Type:A:with wire Colour:Black Material:Plastic Size:121x100x25mm Package Contents: 1 * 2.1 channel BT amplifier board 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.