Mr. Gasket Ultra-Seal Valve Cover Gaskets are made from a high-density and superior quality blend of cork and rubber gasket material with locating tabs on them. They are laminated with a steel core for extra rigidity. The valve cover builds a positive seal by controlling the swelling of gasket material when exposed to hot engine oil. A black latex rubber coating is applied to the exterior of the gasket to help seal minor flange irregularities. The thickness of the gaskets present an additional valve train to cover clearance. They eliminate the possibility of oil leakage and are unshrinkable as well as non-sticky. These valve cover gaskets are ideal for stock replacement use and are designed to suit high performance street race, drag race and oval tracks. They can be used as a replacement for shaft rockers.