6 Set Engine Pistons Rings Kit with 84mm Diameter for use in compatible 2006-2013 E82 E90 E60 E89 E71 135i 335i 535i 740i N54B30 models. Includes part numbers 11257610295 and 11257577586. Designed for engine rebuilds, this piston ring set helps restore compression and reduce oil consumption. Each kit contains six complete piston ring sets sized to fit 84mm bore applications. Proper installation requires standard engine machining procedures and correct gap settings. Disclaimer: This is a compatible replacement part. Any brand or model mentioned is for compatibility demonstration, not endorsement.