4 x N18 N13 Engine Piston and Ring Set A C STD Ø77mm 11257601181 for R55 R56 R58 R60 118i 4X Countryman Paceman Cylinder Bore: 77.00 mm Compression Height: 28.5 mm Land Height: 5.5 mm Length: 51.2 mm Bolt Length: 48 mm Bolt Diameter: 20 mm Recess Diameter: 34.7 mm This piston and ring set is designed for use with the N18 and N13 engines found in R55, R56, R58, R60, Countryman, and Paceman models.The set includes four pistons and corresponding rings, each manufactured to match a cylinder bore of 77.00 mm and a compression height of 28.5 mm.Components are constructed to support engine under normal and sustained load conditions.The design allows for direct replacement with components, facilitating straightforward installation without the need for specialized tools. Important: This product is an aftermarket alternative.Brand names mentioned serve only to show which devices it fits.