Stainless Steel 304/304L Pipe Fitting, Nipple, Schedule 40 Welded, 1" X 3" NPT Male Nipple for connecting and extending pipes Male National Pipe Taper (NPT) threads for connecting female threaded pipes Made of stainless steel 304L for strength Low carbon content to ensure greater resistance to corrosion Meets standards ASTM A733, ANSI B1.20.1, and ASTM A312/SA312 for quality assurance