1. 16-300Ω Mini HiFi headphone amplifier, It is delicate, compact, , and portable that it can be carry conveniently.2. 3.5mm AUX input and output, SNR 100Db and +N 0.0003%, possibility to output not just louder sound, but a and more real stereo sound without distortion.3. Two-stage gain switch enhances the signal input into the amp circuit for optimal performance of the headphones4. Aluminum matte , fashion design provides you a comfortable handheld feeling while the aluminum matte makes it .5. Rechargeable lithium battery, it adopts a rechargeable lithium battery with 1000mAH capacity, which allows it to stay working more than 8 hours.Universal compatibility, it can remarkably compatible with a various of digital devices, such as MP3 MP4 mobile phone computer.HiFi headphone amplifier, delicate, compact, , and portable, which convenient to carry, can output remarkable sound without distortion.Lithium battery capacity: 1000mAHAmp using time: more than 8 hoursAmp battery voltage: DC3.7V - 4VAmp internal working voltage: ±4VSNR 100Db+N 0.0003%Output Power: 40Mw in Impedance 16ΩAdapted Headphone Impedance: 16-300ΩDimension: 95 x 52 x 13mm(L x W x H)Color: BlackMaterial: ABSPackage Contents:1 * Headphone amplifier1 set * accessoriesOnly the above package content, other products are not included.Note: Light reflection 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.