High-quality products for long-term reliability. Manufactured from premium fuel-resistant materials that will not creep, crack or become brittle. Aluminum Foamette Material (AFM) gaskets feature an aluminum core and a chemically blown, compounded nitrile synthetic rubber coating that is bonded to the outside layer; do not require gasket sealer. Made in the USA. Fits 99-17 Twincam. Replace OEM 18635-99.