Compared with potentiometer tuning, the volume control of electronic tuning is more precise. Using Bluetooth 5.0 main control chip, good transmission effect and high stability. With button control, there are control up and down music, volume increase and decrease, play, pause, switch machine, etc., The Bluetooth audio signals of mobile phones, laptops, and tablets can be received through this Bluetooth to the stereo amplifier output. The audio interface can also be connected to ordinary earphones with 3.5mm interface, which can turn ordinary earphones into bluetooth earphones (without microphone, no Support voice chat). Note: Only one Bluetooth stereo power amplifier board (no other accessories), users need to bring their own USB adapter and mini power supply line Maximum receiving distance: more than 10 meters Power output: stereo 2x5W Output mode: AB/D selectable Drive speaker impedance: 2-4-8 ohm speaker speaker Power supply interface: Micro-USB 5V DC (recommended 5V/3A, such as 5V/2A power supply, because the working current in D mode is large, it needs to be switched to AB mode, it is recommended to play more power in 5V/3A D mode Big) Headphone output interface: 3.5mm stereo Speaker output interface: 2x2PIN / 5mm pitch (can not be output to power amplifier) Speaker: 2-8 ohm 5-10W speakers can be connected respectively, 4 ohm 10W speakers are recommended. Installation: When installing the Bluetooth board, try not to place the Bluetooth antenna close to metal parts, so as not to affect the transmission distance. Colour: blue Material: plastic Package Contents: 1 * 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.