1/4 MNPT H style plugs are made of case hardened steel and plated to resist rust. T style plugs offer air flow of up to 67 SCFM, making them perfect for larger tool applications requiring more SCFMs. H style couplers have a 3/8 basic air flow size and a maximum of 300 PSI. Product Features:1/4 male national pipe threadMaximum of 300 pounds per square inchAir flow of 67 standard cubic feet per minuteMaximum temperature of 250 degrees Fahrenheit