Stainless Steel 316/316L Pipe Fitting, Nipple, Schedule 40 Welded, 1-1/2" X 4" NPT Male Nipple for connecting and extending pipes Male National Pipe Taper (NPT) threads for connecting female threaded pipes Made of stainless steel 316/316L for greater strength than steel 304 Low carbon content to ensure greater resistance to corrosion Meets standards ASTM A733, ANSI B1.20.1, and ASTM A312/SA312 for quality assurance