Notice: - If it is used in a car (12V voltage), please use the car cigarette lighter power supply. Connecting to the car battery will 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 will be burned out. - If it is for household use, please use a 12V 2A power adapter. Features: - Mini HIFI digital bluetooth audio power amplifier. - Suitable for U disk, AUX input, MP3 format play, support bluetooth wireless connection. - Two main channel output, left and right channel outputs are interfaces for speakers. - The machine supports bluetooth operation, and supports line input. Specifications: Product Name: Power Amplifier Color: Blue Channel: 2.0 CH bluetooth: Support Input Voltage: DC 8-24V RMS Power: 20W+20W Max. Output Power: 200W+200W Transmission Distance: 15m (Unobstructed) Input Method: bluetooth+AUX+U Disk+USB Sound Card Protection Mechanism: Power Supply Reverse Connection Protection, Short Circuit Protection, Self-recovery Overheating Protection. Size: 7.7*6.2*2.2cm/3.0x2.4x0.9in Package Included: 1 x Power Amplifier ( Not Included Power Adapter ) Notes: - If you want to use it as a household amplifier, you need to buy a 220V to 12V switching power adapter.