Features: SK01 is a high-powers headphone amplifier with tone control (highpitch, middle bass), highand low gains settings, bypass modes, andloudness functions. The tone control function allows you to customize your preferences for sound and compensates for any shortages in the headphones or audios system. The highgain and low gains settings are suitable for headphones with different impedances. The bypass modes provides reproduction of original sound. The loud function allows you to immerse yourself in the world of musics on a peaceful night. Upgrades your audios setups with this SK01 amplifier & preamplifier. Enhances the quality of your headphones, power amplifier, and active speakers. Immerse yourself in clear sound and enjoy every detail. Specifications: Material: aluminum alloy Size: approx 121x51x43mm/4.76x2x1.1inch Model: SK01 Input: 3.5MM line input Output: 3.5mm headphones, 6.35mm headphones, 3.5mm line output Power supply: 5V Power input interface: USB Type-C THD: