With a quantity of three pieces, the Nut,8mm is the most used part in the CYLINDER/PISTON(S) diagram.
Some items from this specific schematic: Ring-set-piston Ll,o/, Bolt-flanged-small, Ring-snap, Bolt-flanged-small.
The Cylinder/piston(s) is made up of components including this Cylinder-comp-engine which is the most expensive.