Built-in high capacity batterySupport charging over voltage protectionSupport 16~600 Ω impedance earphoneSupport output volume adjustment and bass adjustmentSupport one 3.5mm headphone port and one 3.5mm input portType-c port for chargingAluminum alloy material, full of textureThis is built-in battery portable HIFI headphone amplifier,which support charging and adjusting volume and bass.Using 3.5mm cable connect it to your PC,smartphone and game console, etc.it used to improve the volume and sound quality of headphones.Input port:3.5mm(TRS)Headphone port:3.5mm(TRS)Charging port:Type-cBuilt-in battery:3.7V/1400mACharging voltage:5V/500mAStandby power:12mAMaximum working current:55mADuration:≥24 hours16Ωheaphone power :48mW32Ωheaphone power:62mW150Ωheaphone power:30mW300Ωheaphone power:18mW600Ωheaphone power:10mWMaximum output Vp-p:8.2Vp-pTHD:0.02%Signal to noise ratio:100dbFrequency response:20hz~20KhzCross talk: 100dbSound balance:0.3dbWorking environment temperature:-20 to +60℃Colour:blackMaterial:Aluminum alloyPackage Contents:1 x HIFI Headphone Amplifier1 x 3.5mm audio cable1 x Charging cableOnly 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.