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 ) (full volume may also be ) 3. After test is completed, the battery can be connected to power supply after receiving (the 24V battery is not allowed, because battery may 25V after being fully , and capacitor on board is 25V, there is a risk of explosion ) 4. It is not possible to connect 24V battery of a truck, because charging voltage reaches 28-32V when truck is on fire, and it will burn Maximum Power Per Channel: 30W Model Number: Bluetooth 5.0 Power Amplifier Board Channels: Mono Power Amplifier Board colour:Green Material:plastic Package Contents: 1 x Amplifier Board 1 x USB line Only above package content, other are not included. Note: Light and different displays may cause color of item in a little different from real . The measurement allowed is +/- 1-3cm.