Wiseco leads the performance aftermarket by producing the highest quality forged pistons in the U.S.A. Wiseco is unique because they forge all of their own pistons in-house, and produce all of their own forge tooling in the U.S.A. This allows Wiseco to control all aspects of their manufacturing process from raw bar to skirt coating on the finished parts. Extreme racing conditions demand the strength and toughness that only forged pistons can offer. Compared to cast pistons, forgings are tougher and more durable, and will stand up to the abuse that high performance motorsport applications require. Most castings are brittle, have no grain structure and tend to fail catastrophically when the material yield strength is exceeded. Forgings have condensed grain that is aligned to the features of the part, which produces higher mechanical properties, and resistance to impact and fatigue. Each forging is designed to optimize the strength-to-weight ratio, and maximize performance. Much stronger than stock. Tight tolerances for quiet running. More hours with peak performance between piston changes. All pistons include rings, wrist pin and circlips. Note: Image is for reference ONLY, actual contents will vary based on fitment. Important note: This piston is for a stock sized bore. Please measure your cylinder to check clearance before ordering. Detailed Specifications: Bore size: 39 mm (Standard). Compression ratio: 11:1.