Those are what I got from Moss...not the size, but the unmarked 4 ring style...about 5 years ago. The 4 ring was not stock, so I went to TRF looking for a "more correct" 3 ring piston. They were also unmarked! Anyway, after weighing the complete sets, it turned out the 4 ring set was MUCH lighter than the 3 ring set. I went with the 4 ring set on my build.