The Shredder is a clone of the famous Marshall Shredmaster that was fairly prominent in the 80s. The Shredmaster was basically that "Marshall in a box" tone that so many people used in their clean amps to emulate the huge Marshall sound. Whether they were successful at achieving the tone is another thing... This kit includes volume, bass, middle, treble and contour knobs all housed in a small 125B enclosure which is roughly half of what the original one was. On top of that, this pedal is true bypass.
BYOC's clearly laid out instructions make this build very easy. All the resistors, capacitors and other components are clearly labeled. They tell you what to watch out for and how to insert certain components such as polarized capacitors. On top of that, they even show you some modifications you can do to this circuit to help make it your own custom distortion/overdrive/fuzz.
To be honest, I'm not exactly a huge fan of this pedal. Marshall advertised this circuit as a "Marshall in a box" sound, but it never really did sound like a Marshall. It sounded exactly like it was -- a pedal. The sound itself is actually kinda like a mix between a distortion and a fuzz pedal. It can get really aggressive, but it can also be used as a slightly boost to help bring your amp into overdrive. The actual quality of the pedal is very high, so there's little that can go wrong down the road in terms of reliability.
Those looking for a distortion circuit that gives that Marshall tone might want to check this pedal out. It won't turn your JC120 into a roaring JCM800, but it'll at least give a similar vibe to where you can pull out some ripping 80s licks without much of a problem. On top of that, it's true bypass, so it's guaranteed not to suck any tone from your rig.