From the seller:

Professionally maintained and teched prior to shipment. • Selectable auto (classic dbx) or manual (variable Attack and Release) compression • Contour switch removes unwanted low frequency information from detector circuit • Selectable OverEasy® or Hard Knee compression modes • PeakStopPlus™ limiting for setting maximum allowable level with minimal distortion • SC Ext and SC Mon for setting up and monitoring external devices for gating function • True differentially balanced gold-plated XLR and 1/4" inputs and outputs • True RMS level detection • Precision metering of input level, output level, and gain reduction • True stereo or dual mono operation • Switchable +4dBu or -10dBV operation per channel