Features: Built-in bluetooth chip, perfectly matches various devices, supports bluetooth connection and playback of multiple devices. Built-in Bluetooth receiving function, can receive Bluetooth music from mobile phones. The smart market is compatible with various mobile phones, computers, CD players, etc. Bluetooth wireless connection, 15m stable transmission. Support external 7.4V rechargeable battery, can be with DC5V charger; (7.4V rechargeable battery and charger not included). Note: The printing/appearance from batch to batch, but it not affect the use Specification: Name: Car Amplifier Board Support voltage: 220V/12V/24V Output power: 15W+15W Channel: Mono bluetooth: 5.0 bluetooth call: not supported bluetooth music: support FM radio: support USB: support Microphone: support TF/Storage Card: Support Remote control: support Subwoofer adjustment: support NOTE:VERY IMPORTANT!!! It must connect a 7.4V battery to open. this is very important for power on. Colour: Black Material: Iron+PCB Package Contents: 1 x Amp board(Not including 3.7V rechargeable battery) 1 x Remote control(Built-in battery) 2 x Speaker cable 1 x DC Power cable 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.