and high quality TDA7492 digital power amplifier chip, optimized design, circuit design, excellent sound quality, substantial power. DIP switching amplifiers can be adjusted directly for greater gain and enhanced damping capabilities. standard: Power supply: 2.1 interface, 8 ~ 25V DC power supply Audio input: stereo input with Bluetooth connection, utilizing a Bluetooth chip with high software compatibility Output impedance: 8 ohms (best 4, 6, 8, 16 ohm impedance compatible with speakers) Output power: combined with 5532, output power (25V supply, 6 ohm output impedance 2 * 50W, 8 ohm output impedance 2X40W dual channel), dial switch allows for convenient adjustment of amplifier gain for improved speaker performance. Usage: Connect the power and wait 3 seconds until the LED blue light and red light flash alternately, then use your device to find the Bluetooth module, you will discover the audio device, and then connect it for automatic memory connection. 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 to differ slightly from the actual product. The measurement allowed error is +/- 1-3cm.