[Product Parameters]: 4 Euro 2x5W [Power Interface]: Micro-5P (with reserved 2.5mm welding port) [Input Voltage]: 3.7V-5V [Amplifier Working Mode]: Switchable Class AB and Class D [Signal to Noise Ratio]: 90dB [THD+N]: -70dB, Crosstalk: -86dB Color: Black Material: Plastic DNR: 91dB [Output Interface]: Speaker output port x 2 groups (one group for left and right channels); recommended to connect 4 ohm 5W-50W power speakers Users can freely switch between Class AB or Class D working modes according to sound preference and power configuration. [Features]: Power switch and volume knob are integrated. When the sound is adjusted to the minimum, turn counterclockwise until a click is heard to turn off. Turn clockwise to turn on. Powered via Micro-5P interface; compatible with standard mobile phone charger and 5V2A USB cable. [Product Usage]: Can connect audio signal from mobile phone, laptop, or tablet to stereo power amplifier output via 3.5mm audio cable Package Contents: 1 x Amplifier Board 1 x USB Cable 1 x Audio Cable Only the above package content is included; other items are not included. Note: Lighting and display differences may cause slight color variations between the image and the actual item. Measurement error allowance is +/- 1-3cm.