Threaded fitting NPT elbow with two female NPT connectors.
National Pipe Taper (NPT)
NPT is a standardized fitting that is commonly used for joining pipe. Due to the tapered threads (wider diameter at the base of the threads, similar to a trapezoid) the male fitting will tighten the further it is threaded into the female. NPT follows the technical standards provided by the American National Standard Pipe Thread standards, often called national pipe thread, which is often where the confusions with NPT arises, as NPT is specifically an acronym that refers to tapered pipe.
Threaded Female NPT Elbow (FNPT)
Connection Type: FNPT