1. This product is full of materials, featuring high performance and high price, and is a high-quality amplifier specially provided for HIFI music. With AUX and Bluetooth two audio input methods, two in one2. Potentiometer to adjust the volume, with a switch, easy to control the volume, very suitable for DIY speakers. With filter inductance, the sound is mellow and clear.3. 5.0 Bluetooth version, higher transmission efficiency and longer transmission distance. Using TPA3116D2 Class D chip, even at high operation, the distortion is less than 0.1%, and the modulation frequency is up to 1.2MHZ. Built-in filter capacitor can filter out noise and make vocals clearer4. There are two audio input methods, you can directly connect to wireless Bluetooth 5.0 or select the headset (AUX) input. Module can be controlled freely within 15 meters. BT amplifier with protective shell, support reverse connection protection, overvoltage protection, undervoltage protection, overheat protection, short circuit protection5. Please use a adapter with sufficient to connect the amplifier board, otherwise the sound will be distorted. And that the AMP board is from the wifi signal.Working voltage: DC 5V-27VCommunication distance: 15 meters (maximum)Channel: Two-channel stereo outputOutput impedance: 4ohm ~ 8ohmMatching speakers: 30W ~ 200WBluetooth: BLE 5.0Working temperature: -40 ~ 85 Working humidity: 0% ~ 95% RHcolor:BlackMaterial:plasticsize:110mm x 70mm x 21mmPackage Contents:1 x -502C Stereo Bluetooth Amplifier Module2 x Acrylic shell4 x 12mm Copper column8 x 8mm Screw1 x Steel nut, screw mat1 x 20cm cable1 x Screwdriver1 x Knob1 x Heat sinkOnly 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.