It can be used as a preamp or volume control for PC/ Portable all-in-one decoder and headphone amplifier, suitable for //Switch desktop active speakers Supports USB Type-C/optical coaxial digital input, 3.5mm headphone and RCA output Supports headphones with microphone, with high and low volume, volume knob, free control PC-USB support:XP//W8/W10//linux Model number :K5PRO Frequency response :20Hz-20KHz : 98dB Terminal impedance :2-8 Distortion degree :0.003% Amplifier output power :1000mW/16, 500mW/32 300mW/64, 150mW/128, 80mW/300 Headphone connection impedance :16-300 Audio input interface :Type-C, fiber, coaxial, microphone Signal output interface :3.5mm earphone /RCA PC-USB support :XP//W8/W10//linux PC-USB supports input signal sampling rate: up to 24bit/96kHz Fiber/coaxial input sampling rate: up to 24bit/192kHz Colour:As Shown Material:Aluminum alloy Size:11.2x9.5x3cm Package Contents: 1 x Headphone amplifier 1 x 3.5mm headphone splitter 1 x Two-USB-AC to C cable 1 x Optical fiber cable 1 x English manual 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.