Features: Please pay attention to the installation of the heat sink. After sticking the heat dissipation silicone to the heat sink, then stick the silicone side of the heat sink to the power amplifier chip; note that the metal for shell of the heat sink must not be in contact with the surrounding components to avoid short circuits; When this product is powered on without any external audio device, the default is Bluetooth-compatible mode. If you mount an external playback device such as inserting AUX or U disk, the default is AUX or U disk playback mode when power on; during playback, follow the principle of prior device insertion, such as inserting AUX during Bluetooth-compatible playback, then immediately switch to AUX If you insert U disk, it will immediately switch to U disk playback; The power supply range of this product is 5-26VDC, for standard 5.5-2.1/2.5 power adapters; It is recommended to use a 12V/24V standard power adapter with a current output of more than 10A. The selection of the power supply is related to the power of the speaker used. If it is to promote the 4 Q speaker, the recommended power supply is below 2OV, and the 8Q speaker recommends the 24V power supply. Specifications: Material:Metal Power supply: for DC 5-26V/10A or above Bluetooth-compatible Version: 5.0 Audio Channel: 2.1 channel Audio Input: Bluetooth-compatible+AUX+U Disk+USB Sound Card Audio Output: Left and Right Channels + Subwoofer + 3.5mm Stereo Port Frequency Range: 20HZ--30KHZ Output Power:50W+50W+100W Electrostatic for protection, overcurrent for protection, short circuit for protection, overheating for protection Note: Please allow 1-2cm errors due to manual measurement,pls make sure that you do not mind before you order. Due to the difference between different monitors, the picture may not reflect the actual color of the item. Package includes: 1x Upper Cover 1x Lower Cover 1x PCB Board 8 x M2x4 mm Screws 4 x M2x18 Copper Pillars 4 x M2x5+4 Copper Pillars 5x Knob Caps 1x Screw Driver