Multi-headphones amplifier. Input level control. 4 channels with independent level controls. Channels 1 and 2 have balance control. Channels 3 and 4 balance knob has been snapped off. Input level matcher control on rear panel. Fully serviced and working well. COsmetic issues are the previous mentioned knobs snapped off, power button has been replaced, input knob is damaged but functional. Top cover has some scratches and is tarnished in one area. Well designed unit.