This 1/2 Inch Lead Free Center Back Entry Pressure Temperature Gauge Is Used In Commercial, Residential, And Institutional HVAC Applications. It Features A Black Enamel Steel Case, Kostil Polymer Window, 1/2 Inch NPT Connection, Bimetal Spiral Spring, And Copper Alloy Bourdon Tube Pressure Element With ASME Type B Accuracy. This Gauge Features A 3 Inch Dial With Pressure Rating Scale From 0 To 50 PSI And Temperature Range 60 To 320 Degrees F.