EST (Extreme Sealing Technology) gasket kits include embossed stainless steel head, base, and rocker gaskets covered with a proprietary rubber material. Head gasket material allows heat to be drawn away from the combustion ring and dissipated evenly across the gasket surface to eliminate hot spots and gasket failure. Sets contain all the necessary gaskets, seals, and O-rings to rebuild the top end from the cylinder base upward. Made in the U.S.A..