With a quantity of two pieces, the Ring-snap is the most used part in the CYLINDER/PISTON(S) diagram.
Some items from this specific schematic: Ring-set-piston,std, Ring-set-piston L,o/s, Pin-piston, Piston-engine.
The most reasonably priced component used on the An112d6f Kazer 2006 Canada Cylinder/piston(s) is the Pin,dowel,8.2x10x14.