Please use a linear power supply, the ripple is small, and it is not easy to generate hum. Stereo audio two-way input four-way output, can directly push four headphones or external power amplifiers do not affect each other, power supply: DC5-19V, the magnification is about 5 times, the potentiometer controls the volume of each output separately. Using the high-current op amp NJM3414A from Japan JRC, the maximum output current is 70ma, which can provide good large dynamic fidelity output. colour:black Material:plastic size:128x53mm Package Contents: 1 x Stereo Mixer Only the above package content, other products are not included. Note: Light shooting 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.