The PI is the answer to people asking me, "What's the best muff for that 90's alternative sound? The sound to give you the big, open, gritty, grindy, fuzzy sustain of Mudhoney, Nirvana, Sonic Youth, etc?"
I looked at all the late 70's Ram's Head and early 80's Black and Red muffs and noticed they were very similar. I decided to go through all the versions and come up with one version I felt had the best of them all and the result is the PI. It has a huge, open grind with added low end to give the tone a punchy feel.