Product model: -502M Audio input: Bluetooth+AUX+U disk+computer USB (plug and play) Adapter power supply: DC5-24V (high voltage is recommended for high power) Adapted speakers: 10-100W: 4-8 ohm Number of channels: left and right dual channels (stereo) Bluetooth version: 5.0 ( more than 15 meters without obstruction) Bluetooth name: Wuzhi audio Protection mechanism: overheating, overcurrent, short circuit protection Power supply voltage applicable power: 12V--8 ohm/12W+12W, 4 ohm/20W+20W 15V--18 ohm/18W+18W, 4 ohm/30W+30W 19V--8 ohm/30W+30W, 4 ohm/40W+40W 24V--8 ohm/40W+40W, 4 ohm/50W+50W 1. Use the power amplifier board as far away as possible from the WIFI signal (router) 2. The recommended power supply voltage is DC 5~12V/24V, if it exceeds 26V, the chip will burn. 3. The power supply current is recommended to be above 2A. 4. The speaker cable should not be too long, and that it is suitable within 1 meter 5. Pay attention to static electricity protection. Before touching the power amplifier board, you must first release the static electricity on your hands to avoid static electricity from breaking down the chip. Bluetooth chips are more sensitive to static electricity. 6. It is recommended to adapt the speaker with a rated power of 40W and above to avoid the speaker from heating and burning colour: black Material: ABS+metal size: 60x60x29mm Package Contents: 1 x 50W+50W stereo bluetooth digital power amplifier board Only the above package content, other products are not included. Note: Light 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.