45 Degree Elbow is also known as “45 bends or 45 ells”. The 45° pipe elbow is used to connect tubes at a 45° pipe angle. As the name suggests, this is a pipe fitting device that is bent in such a way to produce a 45° change in the direction of flow of the fluid/gas in the pipe.http://www.zhijusteel.com/elbow/45-degree-elbow/