In the '80s, everybody in the MI biz got into the rack game, and Pro Co was no different. Unlike a lot of the antiquated remnants of the rack boom, though, Pro Co's R2DU rack unit was (and still is) a really great and useful piece of guitar gear. Far from being some flashy technological marvel, the R2DU is just two classic LM308 RAT circuits in a single rack box, with a simple two-button remote footswitch for switching between them. They could also be cascaded together for a ferocious, dual-rodent onslaught. The R2DU was only produced for four years, from 1984-1988, but there must have been a fair number of them made, as they come up on the secondhand market with some regularity—often for very fair prices.