Quad compressor/limiter. 4 chan (2 linkable in pairs) comp/limiter. Lo-pass filter, sweepable 20hz-20khz. Compand, threshold, ratio, gain, attack, release, and limit knobs. Optical, link 1/2 (3/4), auto and bypass switches. 10-led metering of gain reduction. XLR and 1/4" in/out with side chain input. Nice performance, good build quality! #9 condition with some minor rack rash. With manual.