This 45 degree elbow is used to connect a pipe to a fitting at a 45 degree angle. Manufactured to ASTM and ANSI standards. They can be used in many plumbing applications, including water supply, drainage, sewers, vents, central vacuum systems, compressed air and gas lines, heating and air conditioning, sump pump drains, and other locations where plumbing fittings would be used to join sections of pipe.