Cometic C9721 Replacement Gasket/Seal/O-Ring High-quality products for long-term reliability Manufactured from premium fuel-resistant materials that will not creep, crack or become brittle Gaskets Available in multiple types to best Suit the intended application Extreme sealing technology (Est) gaskets feature embossed Steel gaskets covered with a proprietary rubber material or solid Copper, depending on the application MULTI-LAYER Steel (MLS) gaskets feature two outer Viton-coated embossed spring Steel layers with an inner Steel layer to provide additional support