This HiFi headphone amplifier, delicate, compact, lightweight, and portable, can improve your smartphone sound quality, making it possible for you to enjoy HD clear pure stereo sound without distortion. You're worth it! Mini HiFi Amplifier: It is delicate, compact, lightweight, and portable so that it can be carried conveniently. 3.5mm AUX Input and Output: 3.5mm AUX input and output, 95DB SNR and THD+N Less than 0.006%, make it possible to output not just louder sound, but also sharper and more real stereo sound without distortion. Rechargeable Lithium Battery: It adopts a rechargeable lithium battery with 200mAH capacity, which allows it to stay working long time. Compatibility: It is specially designed for mobile phones, but also can be used to car o, outdoor speaker and so on. HIFI Sound: Noise reduction function, and distortion with enhanced dynamics, perfect pure stereo effect, HD voice music sound quality optimization Output power: Max: 300mw * 2 / 16 Oh Frequency / response: 2-27KHZ 27KHZ Signal to noise ratio: 95DB Dynamic range: 90DB Separation: 70DB Distortion: less than equal 0.00 6% Input impedance: 32 Oh Output impedance: less than equal 200 Oh Operating temperature: -40 Celsius ~ 60 Celsius Storage temperature: -40 Celsius ~ 85 Celsius Storage humidity: 10% ~ 90% Battery: Built-in lithium battery, 200mah (Charged by a Micro-USB cable) Battery endurance: Approx. 30 hours Size: 70 * 25 * 10mm / 2.76 * 0.98 * 0.39inch Color: Black Material: Aluminum alloy Package Contents: 1 * Headphone Amplifier 1 * English manual Only the above package content, other products are not included. Note: Light shooting 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.