Wiseco S522 Piston Wrist Pin Fits Wiseco piston part number series: 4156M, 4289M, 4362M, 4394M, 4395M, 4668M Chromed piston pin (for 4-cycle use only) Outer diameter: 15.000mm x length: 56.00mm x inner diameter: 9.00mm Weight: 44 grams High quality alloy pin is compatible with most OEM pistons