Features and Benefits: 1/2 female national pipe thread Maximum inlet pressure of 300 pounds per square inch Air flow of 99 standard cubic feet per minute Maximum temperature of 250 degrees Fahrenheit Buna-N seal 1/2 FNPT G style couplers are used in applications that require over 60 SCFM. There are two Milton G Style couplers but both will function the same with G style plugs. Milton G style couplers are made of steel and are plated to resist rust. With a 1/2 basic flow size these plugs offer up to 99 SCFM making them the highest SCFM rated couplers. Maximum pressure of 300 PSI.