1.Mini HiFi headphone amplifier: All-metal shell, small size, exquisite, small, light, ultra-thin portable HiFi headphone amplifier, help you enjoy high-definition clear and pure stereo without distortion.2. Butterworth circuit design: Butterworth automatically adjusts height and bass automatically, increasing sound density and high and low frequency gain.Vibrant, dynamic, round low frequency, strong quality, to provide you with the feeling of HIFI stereo system.3.Headphone amplifier not only can output louder sound, but also output clearer, more real stereo sound, and distortion low.4. Rechargeable lithium battery: The HiFi headphone amplifier uses a rechargeable lithium battery with a capacity of 220mAH, which can keep working for a long time.Just plug and play, without any unnecessary switches or buttons, it will automatically detect the installation and start when the headset is plugged in. 5. Universal compatibility: The headphone amplifier can be significantly compatible with digital devices, such as MP3 MP4 mobile computers, headphones, active speakers, power amplifiers, car speakers.Battery capacity: 120 mA Output power: 300mw * 2 / 16ohm Frequency response: 2-27KHZ Signal to noise ratio: : 95DB Dynamic range: 90DB Resolution: 70DB Distortion: ( + N) 0.006% Input impedance: 32ohm Output impedance:less than equal 200ohm Working temperature: -40 Celsius ~ 60 Celsius Battery charging interface: Microphoneusb interface Efficient charging and radiation suppression circuit: 40 minutes of charging, HIFI can be used continuously for 5 hours, and standby battery life is up to 200 hours Colour:black Material: ABS Size:3.5mm55*22*11mm Package Contents: 1x headphone amplifier 1x USB data cable 1x audio cable 1x audio adapter 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.