Dual reverberation. Very good cosmetics, obvious ware, good faceplate. Fixed/floating limiting threshold, in/out attenuations, and bass/mid/sweepable EQ per channel. XLRs as well as barrier strips on back panel. Shortened/tightened springs for less muddy, brighter sound (tuned spring pans for ch matching). Altered input/output circuit to improve spring bandwidth and added spring dampers (foam) to reduce noise. Extra control added for high frequency enhancement, excellent for the "huge snare" sound. All switches and controls cleaned.
While great for its era, there are now similar units that do the sound imaging better than the 111b. The Behringer Edison or Ultra Fex, or DEQ2496 are all more sophisticated with better imaging correction, true stereo, etc and far more flexibility to reach into the depth of the mix. Low, mid, and highs can be separately adjusted.