ProX racing pistons are precision machined on the latest, state of the art CNC equipment. The same low-expansion, low-friction piston alloy is used as is used for all major Japanese engine manufacturers. ProX Piston Kits are a first class solution to replace the original piston in your motorcycle, scooter, moped, ATV, personal watercraft and more. ProX Piston Kits for sleeved cylinders are available in standard size and a wide range of oversize's. The availability of oversize's up to 2 millimeters significantly helps to increase the lifespan of a cylinder by offering more re-boring possibilities. ProX racing pistons for plated cylinders come in standard size, as well as in A, B, C, D+ oversize's. All ProX Piston Kits are supplied complete with pistons, piston rings, wrist pin and circlips, ready to install.