ProX Piston Kits are comprehensive coming complete with: Piston / Ring Kit / Wrist Pin / Cir Clips. ProX also offers oversized piston options in order to follow manufaturer Piston to Cylinder Wall clearances. ProX 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, etc.!