Only MAHLE Original can say that it is the largest manufacturer of piston rings in the world today. This stability leads to a tremendous research and development foundation, which guarantees that MAHLE Original is the highest performing ring in both light vehicle and performance applications. MAHLE Original piston rings lead the way in ring technology and innovation for the Aftermarket ? after all, MAHLE is the largest manufacturer of piston rings in the world. MAHLE Original rings are at the forefront of light vehicle piston ring technology. Extensive OE connections mean that MAHLE Original rings have the technological edge. Things like the CP-20 oil ring, narrow compression rings, steel compression rings for gasoline engines, low-tension oil rings and coated compression rings for diesels all came from the OE. The MAHLE Original performance line proves time and again that it should be the ring of choice under every hood - regardless of the application. Grey cast iron or ductile iron was traditionally the material of choice for automotive applications - today, steel is preferred over iron by more and more engine builders. Steel compression ring technology has been used in heavy-duty applications for over 30 years. That know-how has become essential to the design and engineering of todays automotive engines. Steel piston rings offer higher tensile strength, higher yield strength, greater fatigue life, and greater hardness while still offering a lower ring mass. These factors lead to better stress resistance, reduced groove pound-out, longer service life, better conformability, superior oil economy, and improved blow-by control while still lowering friction.