[USB Audio Converter] fer The Computer's Audio Signal Through The USB Port, Covert Audio to Optical, Coaxial, 3.5mm or 6.3mm Headphone Jack.Can Also Be Used As An External Sound Card.(Note:5.1 Channel Is Incompatible, Please Set The Audio Output to PCM or LPCM) [16-300 Ohm Hi-Fi Headphone Amplifier ]Supports Most Headphones of High Impedance 16-300 ohm, Signal-to-noise Ratio more than 100Db, + N = 0.0003%, Fully Filter Noise, Enjoy High-quality Audio. [USB Input Volume Control for Headphone Sound]USB inputs,With the Volume Control Knob That You Could Adjust the headphones Volume , [Good Compatibility]Compatible with both and System, For best playback in .Compatible with , , , ,Which Can Be Connected Your Headphones by USB for Playing Games. [Plug and Play]No Driver Required, Plug-and-play for Instant Audio playing and Compliant with All Mainstream Operation Systems. No External Power Required Provides The Easiest Way to Convert Your PC into A Hi-end Music Server. Colour: black Material: plastic Size: 106x66x25.5mm Package Contents: 1 * audio converter(The silk screen is slightly different from the factory) 1 * 3.5mm adapter 1 * USB cable 1 * English Instruction manual Only the above package content, other products are not included. Note: Light 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.