The Korg DRV-2000 is a rack mount multi-effects processor. It specializes in digital reverb, but can also do delay, chorus, flanging, compression, noise gating, etc. Dating from the late 80s, it features a mono 1/4" input, with stereo 1/4" outputs. It can be controlled by the front panel switches and knobs, as well as by MIDI and footswitches in the back.
The sound is great, and holds up among its contemporaries from the likes of Roland, Alesis, Yamaha, etc. The manual is easily available online, in case you'd like to delve further into its abilities.
This unit is in very good shape, structurally. There are scrapes and smudges, and one of the feet is missing. All controls work, the displays are clear.