If it is used in a car (12V voltage), please use the car lighter power supply. Connecting to the car battery cause noise. If it is used in a truck (24V voltage), you need to use a step-down device to reduce the voltage to 12V before it can be used. Otherwise, the power amplifier be burned out. If it is for household use, please use a 12V 2A power adapter. Amplifier type: hifi power amplifier Size: 155x85x45mm/6.1inx3.3inx1.7in Rated voltage: 12V RMS power: 40W+40W Max power: 400W+400W Rated frequency: 20-20KHz Resolution: 47K Distortion rate: 0.1 SNR: 90dB Impedance: 4-16 Power amplifier type: hifi amplifier Interface type: clip Receiving mode; audio input Weight: 0.35 (kg) Mini HIFI digital bluetooth audio power amplifier. Aluminum alloy body, , the body is made of aluminum alloy once, the anode treatment, the overall atmospheres, thick, feel is also very good. for SD Card, U disk, AUX input, MP3 format play, support bluetooth wireless connection. Supports FM stereo radio. Low distortion supplies a clearer, stronger and more powerful sound. With Remote control function. Plug Type:US Plug,it applies to Canada, India,Mexico, Thailand, the , the Philippines,Taiwan and so on. Voltage: AC110V (with 12V 5A adapter) Color: Black Material: Metal Package Contents: 1 amplifier 1 x Remote control 1 x Connector Cable 1 Adapter 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.