1. The power supply of this power amplifier board requires 12-24V 3A DC regulated switching power supply (testing with battery and charger, transformer and AC switching power supply is not guaranteed) 2. 24V 3A power supply, the output power can reach up to 30W 8 ohm continuous power! It can be connected to 30W bass + 10W tweeter (4 ohm speaker may be protected) (full volume may also be protected) 3. After the test is completed, the battery can be connected to the power supply after receiving the goods (the 24V battery is not allowed, because the battery may exceed 25V after being fully , and the capacitor on the board is 25V, there is a risk of explosion!) 4. It is not possible to connect the 24V battery of a large truck, because the charging voltage reaches 28-32V when the truck is on fire, and it burn! Maximum Power Per Channel: 30W Model Number: Bluetooth 5.0 Power Amplifier Board Channels: Mono Stage Power Amplifier Board colour:Green Material:plastic Package Contents: 2 x Amplifier Board 2 x USB line 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.