1. Support reading MP3 music in U disk and TF small memory card 2. Built-in Bluetooth receiving function, can receive Bluetooth music from mobile phones 3. For 3.7V lithium battery, can be with DC5V/1-2A charger 4. With AUX IN external audio input function, can be connected to the computer to play 5. The panel has a wired , which can be used to sing or sing Using power amplifier, rated power 15W, 30W The product is mono channel. NOTE: It must connect a 3.7V lithium battery to open.---this is very important for power on. Type: Amplifier Board color:Black Material:Metal size:194 x 85 x 26mm Package Contents: 1 x 3.7V Bluetooth Amplifier board(Without power) 1 x Remote Control(with battery) 1 x SPeaker Wires 1 x radio antenna Only the above package content, other products are not included. Note: Light 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.