Fits Wiseco piston part number series: 40007M, 40009M, 40010M, 40012M, 40019M, 40020M, 4842M, 4843M, 4904M, 4920M, 4921M, 4927M, 4928M, 4982M, 4983M, 4984M, RC849M, RC850M, RC880M, RC886M, RC888M, RC894M. Superfinished OD (for 2 and 4-cycle use). Outer diameter: 16.000mm x length: 40.00mm x inner diameter: 9.00mm. Weight: 39 grams. High quality alloy pin is compatible with most OEM pistons. Wiseco's engineers utilize the latest in 3D design and finite element modeling software to ensure every Wiseco design is developed to provide the greatest strength and lightest weight for each application. Our in-house dyno facility, equipped with the latest technology, along with our field-testing network, ensure that our products meet the expectations of the demanding motorsports industry.