4pcs Engine Piston Ring Set compatible with engine models 11257618811 11258606459 11257640166.Designed for use with N20B20A 2.0T engines found in certain vehicle models including F30, F10, X3, 328i, 428i, and 528i.This piston ring set helps maintain proper compression and oil control within the engine cylinder.Each set includes four rings: two compression rings and one oil control ring with rail spacers.engineered to meet specifications for fit and function.Intended for replacement or repair applications during engine overhauls. Important: This product is an aftermarket alternative.Brand names mentioned serve only to show which devices it fits.