CN fittings and connectors (KC nipple, King Combination Nipple) is a simple type of fitting widely used for industrial rubber and plastic hoses. The fittings are manufactured from pressed steel pipes (carbon steel, 304 and 316 stainless steel). The hose tail is serrated to mount it to hoses with bands, hose clamps or special crimp ferrules from sheet metal. Hose inner diameters range from 1/4″ (6 mm) to 10″ (250 mm). Carbon steel fittings are zinc-plated (except for weld-in fittings).