I’ve written about the legendary ProCo Rat before, but this is version is a little special because it crams a few different Rats into one nice package.  Without getting to techinally mumbo-jumbally, these use the basic Rat topology and play with the clipping diodes to allow for four different voicings which are selectable via the big red knob on the side.  Within the four voicings are the standard rat (sometimes called the vintage rat) and the turbo rat which is a bit louder and more rough than the standard rat.  There’s also a more clipped setting which is a bit more compressed and smooth than the standard rat, and an less clipped setting which is loud as shit, and tougher than RUN DMC.  They all sound killer with guitar, and the latter is a great option for bass distortion as well.  Rip it up!