Threaded Flange, Raised Face, 1/2 in Nominal Pipe Size, Flanged x FNPT, 3 3/4 in Flange Outside Diameter, 1/2 in Flange Thickness, 3 3/4 in Overall Length, Steel, Galvanized, Class Class 300, For Pipe Schedule 80, 725 psi Maximum Operating Pressure, 725 psi Max. Steam Pressure, 80 Degrees to 780 Degrees F, Number of Bolt Holes 4, 1/2 in Bolt Hole Diameter