Speedmaster valve cover gaskets are manufactured from high quality rubber, which is molded over and vulcanized to a rigid steel frame. They won't leak, blow out, or get sucked in, the way stock or inferior-quality aftermarket gaskets can. These gaskets feature superior-quality rubber and steel, which outlast cork-and-rubber composite designs to provide years of dependable service, especially if you frequently have to remove and reinstall the valve covers.