Discharge Cap For Fan Diameter 18 in For Fan Type Tubeaxial Mounting Hole Diameter 1/2 in Material Galvanized Steel Body Diameter 26 in Bolt Circle Diameter 19 7/8 in Finish Unfinished For Use With 4C661 4TM82 4TM83 Includes Clam Shell Damper Maximum Inlet Air Temperature 200 Degrees F Metal Material Thickness 3/8 in Overall Height 23 1/8 in Overall Length 26 in Overall Width 26 in Product Type Discharge Cap