Sorry if there is a thread on this already, but it is nearly impossible to search for "#4" as a search term. Anyway, my local NAPA does not sell #80 or #83, but they do sell #4. Is this for use with a rotary only? Can I use it with PC, or is it too harsh. If it is OK for PC use, then what is it comparable too in terms of abrasiveness. They said they can probably order me almost any Meguiar's product I want (we'll see about that). Also, where are you guys finding the new Meguiar's brushes and stuff OTC, or are you? I am interested in the Water Magnet MF towel.