The Salco Products (TC4BCDI2A) 4-Inch Ductile Iron Bottom Outlet Cap with Gylon Gasket and Carbon Steel Chain is made out of ductile iron material with a 2-inch ductile iron plug. It fits a standard 5-1/4-inch railroad thread for application to any car manufacturer's nozzle. Comes with 3/8-inch, carbon steel, chain with 16 links, a 4-inch, 304 stainless steel, lock ring, a 3/8 by 2-1/4-inch, zinc plated carbon steel, hex bolt, a 3/8-inch, zinc plated carbon steel, hex nut lock, 2 (two) 3/8-inch USS, zinc plated carbon steel, flat washers, and a 3/8 by 3-1/2-inch, zinc plated carbon steel, S hook. This model includes an easily replaceable Gylon gasket that has a 3-1/4-inch inner diameter and a 5-1/2-inch outer diameter.