This PT Coupling Special Application Series weld nipple is made of type 316 stainless steel and connects hose to welded pipe. This adapter has a barbed stem that creates a leak-resistant seal on flexible and semi-rigid hose when used with a hose clamp (sold separately). The fitting’s butt-end must be welded to pipe. This fitting is made of type 316 stainless steel for higher strength and greater corrosion resistance than type 304 stainless steel. Pipe fittings are components used for connecting, terminating, controlling flow, and changing the direction of piping in many different industries. When purchasing pipe fittings, consider the application, as this will affect material type, shape, size and required durability. Fittings are available threaded or unthreaded, in many shapes, styles, sizes, and schedules (pipe wall thickness). PT Coupling manufactures pneumatic and hydraulic hose fittings for industrial and automotive applications. The company, founded in 1951 and headquartered in Enid, OK, meets International Organization for Standardization (ISO) standard 9001.