The Pro Co "The RAT" is a guitar pedal produced by Pro Co Sound. The original RAT was developed in the basement of Pro Co's Kalamazoo, Michigan facility in 1978.[Numerous variations of the original RAT pedal are still being produced today.
The basic RAT has changed in appearance over the years, but its tone has remained largely the same. Pro Co has also introduced tonal variations of the RAT, including the Turbo RAT and You Dirty RAT, among others.
The Pro Co RAT became very popular in the early 1980s, thanks in part to fame gained by its use by several artists, including Metallica, R.E.M. and Weezer.