The highest-quality gaskets availableCometic head gaskets are constructed from spring steel or graphiteSpring steel gaskets are made from a stainless steel shim design coated with a 0,0001" thickness of silicone on both sidesGraphite material is impervious to fuels, coolants and oilsEngine case rebuild gasket kits include all gaskets needed for lower end rebuild (base gasket not included)Base gaskets and valve cover gaskets constructed from premium fuel-resistant materials- will not creep, crack or become brittle