8Pcs Piston and Rings Set for N63B44C engine, compatible with 750i, 550i, M550i, X5, X7, and 50i models equipped with a 4.4L engine.This set serves as a direct replacement for OEM part numbers 11258600381, 8600381, 11 25 8 600 381, and 8 600 381.Constructed from steel, the pistons are designed to resist wear and corrosion, supporting under demanding conditions.Each set includes eight pistons and corresponding rings, precisely machined to meet specifications for proper fit and consistent performance.The piston size of 88.987mm is engineered specifically for the N63B44C engine platform, functional accuracy and integration within the engine assembly.Designed for straightforward installation as a direct-fit component, this piston and ring set supports efficient engine function and durability. ote: This is a third-party compatible part.Brand/model citations do not imply sponsorship or approval.