So I finally got went ahead and ordered a set of .20 OS RSMACHIENS pistons after hearing good things about them. However, after receiving them I noticed that the tops of the pistons were imprinted with a 0.50 . Now I am in a sort of dilemma because I have no tools or no way to measure these suckers. Basically I would like to know if they sent me the correct size that I ordered or sent .50 OS. If you’re reading this and know what I’m talking about please post. It’ll be greatly appreciated. Thank you.

 

0.020" = .50mm