Fangrui Product Details [product Parameters]: 4 Euro 2x5w [power Interface]: Micro-5p (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 Colour: Black Material: Plastic Dnr: 91db [output Interface]: Speaker Output Port X 2 Groups (one Group For Left And Right Channels), It Is Recommended To Connect 4 Ohm 5w-50w Power Speakers To Use Users Can Freely Switch Between Class Ab Or Class D Working Modes According To Sound Preference And Power Collocation. [features]: The Power Switch And The Volume Knob Are Integrated. When The Sound Is Adjusted To The Minimum, Turn It Counterclockwise. When You Hear A Clicking Sound, It Is Turned Off. Turn Clockwise To Turn It On. Powered By Micro-5p Interface, Ordinary Mobile Phone Charger 5v2a Charging Cable Can Be Used. [product Usage]: Can Connect The Audio Signal Of Mobile Phone, Laptop And Tablet To The Output Of Stereo Power Amplifier Through 3.5mm Audio Cable Package Co