Bluetooth Amplifier Board Yosoo Wireless Digital Bluetooth 4.0 Audio Receiver Amplifier Board TDA7492P 25W+25W 100 Brand New and High Quality After power is turned on, the product automatically goes into pairing mode.The device name will be displayed after the search: SANWU Audi. Power: 2.1 Interface DC 8 ~ 25V power supply. Audio input:Various versions of Bluetooth stereo inputs, CSR8635 Bluetooth chip, Bluetooth V4.0, high software compatibility. Output Impedance: 8 ohms Best (ohm impedance speakers can drive 4,6,8,16).