Both input and output are 3.5mm interface, two-channel signal; One input and two simultaneous outputs, the output can be connected to audio equipment such as headphones or audio amplifiers, and the volume can be adjusted independently; Power supply voltage: DC5V, static working current: 100ma, this machine has a built-in isolated booster power supply, which converts 5V voltage to plus or minus 9v to provide working voltage for the internal circuit. Although the power supply part has been optimized and filtered, it is still recommended to use high-quality Pure power supply can clear and pleasant sound without interference. Gain: 3.5db Input impedance: 100K, output impedance: 16 ohms-600 ohms, maximum output power 32 ohms/500mw. Colour:black Material:plastic+metal Package Contents: 1 x Tone Controller 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.