Prox Racing Parts 01.4221.A Piston Kit Pistons for plated cylinders come in standard size, as well as in A, B, C, D+ oversize's Pistons for sleeved cylinders are available in standard size and a wide range of oversize's Uses the same low-expansion, low-friction piston alloy as used for all major Japanese engine manufacturers Precision machined on the latest, state of the art CNC equipment All ProX piston kits are supplied complete with pistons, piston rings, wrist pin and circlips, ready to install