Mahle Original piston ring sets are designed to be installer-friendly. They are pre-lapped to seat immediately, virtually eliminating break-in time. Ring materials and coatings, as well as ring tension, are all optimized for reduced friction and extended life in each application. The compression rings feature a barrel-faced contact area for more efficient compression and CNC-controlled gap chamfer to optimize compression and reduce blowby. Intermediate rings have a reverse twist design for better groove side sealing, and taper race machining to enhance contact. The CP-20 oil ring assemblies feature a 20 degree ear angle, an exclusive feature that provides the best possible side seal against the cylinder wall, and a special chemical polish on the oil ring expander offers enhanced oil drainback. Mahle Original piston ring sets provide unmatched quality and ease of installation, making them the rings of choice for today's engine builders.