Stainless Steel 316/316L Butt-Weld Pipe Fitting, Concentric Reducer Coupling, Schedule 10, 6" X 4" Pipe Size Reducer coupling for connecting concentric pipes of different sizes Butt-weld, beveled openings for welding pipes together Made of stainless steel 316/316L for strength and ease in welding Welded connections to ensure tight seals and reduce the possibility of leakage Low carbon content minimizes harmful carbide precipitation during welding