A hybrid design forged to harness the best sealing properties of two head gasket types. Composite: pliable, perforated metal-core composite gasket body eliminates coolant and oil leaks. No sealant needed! Stainless Steel: solid stainless cut-ring 'bites' into the cylinder head forming a positive barrier against combustion pressure leaks. No machining required! Designed for use with high static compression or forced-induction engines which are prone to combustion pressure leaks when using typical composite or MLS head gaskets.