Wiseco Semi-Keystone piston rings offer maximum ring seal with less than 1 percent blowby. These rings have a 7 degree tapered compression ring and use high temperature alloys. Their rings can be used in cast iron, nickel ceramic platings (Nikasil), boron composite, and electrofusion bores. They can-not be used in chrome bores unless otherwise stated. Wiseco rings only fit their pistons. They are designed for durability, longevity, and exceptional ring seal for top performance. When you want superior strength, longer life, and improved heat transfer, get Wiseco Semi-Keystone piston rings.