Both input and output are lotus interface, one set of two-channel audio input, five sets of two-channel output, can be connected to five power amplifiers or active speakers, with gain compensation 3 times amplification (9.5db); Frequency range: 20HZ-20KHZ Input impedance: 50K Output impedance: 600 ohms Gain: 9.5db This machine has low noise and high fidelity, and can work stably with power on for a long time Please use a low-ripple power supply for power supply, the power interface is 5.5 x 2.1 inside positive and outside negative Color: Black Material: plastic+metal Package Contents: 2 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.