Input port: 3.5mm(TRS) Headphone port: 3.5mm(TRS) Charging port: Type-c Built-in battery: 3.7V/1400mA Charging voltage: 5V/500mA Standby power: 12mA Maximum working current: 55mA Duration: equal 24 hours 16Ωheaphone power: 48mW 32Ωheaphone power: 62mW 150Ωheaphone power: 30mW 300Ωheaphone power: 18mW 600Ωheaphone power: 10mW Maximum output -p: 8.2Vp-p : 0.02% Signal to noise ratio: 100db Frequency response: 20hz-20Khz talk: 100db Sound balance: 0.3db Bare size: 104.5x63.5x16.5mm Bare weight: 152.5g Working environment temperature: -20 to +60℃ Due to different product batches, the appearance , which does not affect the use. Colour:Black Material:aluminium alloy Package Contents: 1 x HiFi Headphone Amplifier 1 x 3.5mm Audio Cable 1 x Type-C Charging Cable Only 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.