SCE Pro Seal Head Gaskets are designed to for performance or mild racing applications. Gaskets are made from a steel core coated in graphite with 321 stainless fire ring armor. This unique configuration is strong enough to withstand 15lbs. of boost or a 100HP shot of nitrous. Unlike other brands there is no ''o-ring'' behind the fire ring. This allows for a compressible gasket which will not damage aluminum cylinder heads. Each of the SCE component materials can withstand much higher heat than the engine will produce and the components are mechanically assembled without adhesive materials or sealants. This eliminates the possibility of heat related failures. Sold individually.