PC is short for Porter Cable, best buffer out
I'll be ordering a kit in a week
http://www.autogeek.net/optimum-porter-cable-kit.html The PC 7424 is popular as hell and great for a novice since it's dual-action. I can't wait to de-swirl my car and get rid of those thin scratches
http://www.autogeek.net/hk7424.html has tons of deals with the PC.