Features: Built-in Bluetooth chip, compatible with various devices, supports Bluetooth connection and playback from multiple devices. Built-in Bluetooth receiving function, can receive Bluetooth music from mobile phones. Compatible with various mobile phones, computers, CD players, and other devices. Bluetooth wireless connection with stable performance up to 15 meters. Supports external 7.4V rechargeable battery and can be used with a DC5V charger (7.4V rechargeable battery and charger not included). Note: Printing and appearance may vary slightly from batch to batch, but this does not affect functionality. 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: Supported FM radio: Supported USB: Supported Microphone: Supported TF/Storage Card: Supported Remote control: Included Subwoofer adjustment: Supported NOTE: VERY IMPORTANT A 7.4V battery must be connected in order to power on. This is essential for operation. Color: Black Material: Iron + PCB Package Contents: 1 x Amplifier Board (3.7V rechargeable battery not included) 1 x Remote Control (battery included) 2 x Speaker Cables 1 x DC Power Cable Note: Light reflection and differences in display screens may cause slight variations in color between the product image and the actual item. Measurement error allowance is +/- 1-3 cm.