Malleable black iron pipe fittings. Black finish resists rust. National Pipe Threads for creating tighter seals than straight threads. Fed. Spec. WW-P-471-B, ANSI B-16.14 (Dimensions), ANSI B-2.1 (Pipe Threads), Ferrous Plugs, Bushings, and Locknuts, Fed. Spec. WW-P-471-B, ANSI B-16.14 (Dimensions), ANSI B-2.1 (Pipe Threads), Malleable Iron Unions (Class 150), Fed. Spec. WW-U-531C, ANSI B-16.39.
