These requirements cover indicating pressure gauges of the elastic element type usually employed in the high-pressure side of regulators or reducing valves used on compressed gas containers or cylinders of oxygen, hydrogen, nitrogen, and other gases. Such gauges usually have pressure ranges of 0 - 1500, 0 - 2000, 0 - 3000, or 0 - 4000 pounds per square inch (psi) (0 - 10.34, 0 - 13.78, 0 - 20.68, or 0 - 27.56 MPa).