and high quality TDA7492 digital amplifier chip, design optimization, circuit design, sound quality is very good, big . DIP switching amplifiers can be adjusted directly after gain more respect and promote greater damping cushion. standard: supply: 2.1 interface, 8 ~ 25V DC supply Audio input: stereo input and various versions of the Bluetooth connection, using Bluetooth chip CSR8635, Bluetooth V4.0, software compatibility high Output impedance: 8 ohms (best 4,6,8,16 ohm impedance can drive the speaker) Output : join of 5532, output of foot (25V supply, 6 ohm output impedance of 2 * 50W, 8 ohm output impedance 2X40W channel), dial switch can be directly adjusted amplifier gain more convenient, better promote greater horn of damping of use: connect the and wait 3 seconds, until the LED blue light and red light flashing alternately, then you can use your device to find my Bluetooth module, you will find SANWU audio, and then connect it, then you can use memory to automatically connect directly. Colour:red Material:PCB Package Contents: 1 x Bluetooth amplifier board 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.