Features: 1. Supports reading MP3 music from USB drive and TF card 2. Built-in Bluetooth receiving function, can receive Bluetooth audio from mobile phones 3. Designed for 7.4V lithium battery, can be charged with DC 9V/1-3A charger 4. Includes AUX IN external audio input, compatible with computer connection for playback 5. Panel equipped with wired jack for microphone use; features digital power amplifier with 15W rated power and 30W peak power A 7.4V battery must be connected for the device to power on. Battery polarity must be connected correctly as indicated, otherwise the board may be damaged. NOTE: VERY IMPORTANT Material: Plastic Color: Black Package Contents: 1 x Bluetooth Amplifier Board 1 x Remote Control (random style, specific design cannot be selected) 1 x Cable Only the items listed above are included; other items are not included. Note: Lighting and display differences may cause slight color variations between the image and the actual item. Measurement error allowance is +/- 1-3 cm.