The Washer, Plain (646) is the lowest priced item on this Crank - Piston schematic.
A sample from the products for the Crank - Piston include: Piston Ring Set (std), Washer, Plain (646), Piston Ring Set (std), Circlip (6h3).
The Crank - Piston is made up of components including this Crankshaft Assy which is the most expensive.