1. Supports MP3 music playback from USB drive and TF memory card 2. Built-in Bluetooth receiver function, compatible with wireless streaming from mobile phones 3. Designed for 3.7V lithium battery operation; can be powered using a DC 5V/1-2A charger 4. Features AUX IN input for external devices, allowing connection to computers or other audio sources 5. Includes a wired microphone input on the panel for karaoke or vocal use Uses digital power amplifier, rated output power 15W, peak power 30W This is a mono channel amplifier NOTE: A 3.7V lithium battery must be connected in order for the device to power on Type: Amplifier Board Color: Black Material: Metal Size: 194 x 85 x 26mm Package Contents: 1 x 3.7V Bluetooth Amplifier Board (battery not included) 1 x Remote Control (with battery) 1 x Speaker Wires 1 x Radio Antenna Note: The package includes only the items listed above. Other accessories are not included. Note: Lighting conditions and display settings may cause slight variations in color representation. Measurement error allowance is +/- 1-3cm.