This Dixon B series iron wing nut cap for Boss ground joint fittings is constructed of iron for strength, malleability and ductility, high magnetic permeability, and resistance to corrosion. It closes an open end of a wing nut and seals with a Klingersil C-4401 washer (included). For best results, use with washer style spuds. An attached 12" chain prevents loss when the cap is not in use. This cap is for use in non-pressure applications.Hose fittings connect, control, change the direction of, and terminate the flow in piping and hose systems. They are made of brass, stainless steel, galvanized steel, and other materials that resist corrosion, pressure, and wear. Hose fittings have various types of connections, including threaded, barbed, push-to-connect, dry disconnect, and others including those based on internationally-accepted specifications. Hose fittings are used in systems such as air compressors, automatic manufacturing operations, aircraft controls, and tire installation in industries including agriculture, mining, road construction, firefighting, and aviation.Dixon Valve & Coupling Company manufactures pipe and hose fittings and accessories. The company, founded in 1916, is headquartered in Chestertown, MD.