XH-M422 DC12-24V TPA3116D2 50W + 50W Bluetooth 4.0 amplifier board with Bluetooth U disk TF card player Product Description Technology index: Chip: TPA3116D2 Bluetooth transmission distance: up to 20m Voltage: DC 12-24V Power: 50W + 50W Storage: TF card, U disk Efficiency: 90%