1/2\” X 36\” Pipe Nipple, Stainless Steel Schedule 40 Threaded Both End (TBE) NPT 304/304L SS The Nipple Threads are National Pipe Thread (NPT), also known as American National Standard Taper Pipe Thread. This is the common thread used for threaded pipe connections in the United States. NPT is defined by ANSI/ASME standard B1.20.1