I don't know the number on them either. They came in a kit I bought a couple of yrs. ago that I didn't use. I looked all over them and couldn't find a number. When I bought them the salesman told me they were they were the thin ones so that's what I was going by. I measured the thickness and they measured .044 out of the package so I'm not sure how much that would compress to but I doubt they will go all the way down in the .020's like he told me. The bore is also bigger than I was told. I measured them at 4.078-4.081 Sorry about the misinformation. I should have measured them before I spoke. I also should know better than take a salesman's word as gospel.:bootysha: