Gentec 853LCR Series Liquid Cylinder Regulators are specially designed for gaseous withdrawal from liquid cylinders of Oxygen, Carbon Dioxide and Nitrogen. Not for use on high pressure cylinders. CGA540, 9/16in-18RHM, Gas: Oxygen.FEATURES: Vapor side application on liquid cylinders or vessels 0-125 PSI delivery pressure 500 PSI maximum inlet pressure Large 2-3/4in stainless steel diaphragm 500 PSI external pressure relief valve on high pressure side Forged brass body and housing cap Delrin cap bushing for smooth pressure adjustment Stem-type seat assembly for more reliable performance Sintered bronze inlet filter 2-1/2in dual scale outlet gauge Conforms to CGA E-4 Standard for Gas Pressure Regulators