Lightweight forging for instant throttle response and maximum torque Computer-engineered piston skirt profiles provide minimal cylinder-wall friction Offers peak horsepower at a twist of the wrist Anti-detonation grooves and new ring land diameter eliminates ring blow-by, while maximizing engine performance Piston kits include rings, wrist pin and circlips 12:1 Stock Compression Bore Size - 95 mm This product can be used with Yamaha YFZ450 4-Cycle 04-06