Plenum Fan Wheel Type Backward-Curved Drive Type Belt Drive Includes Drive Package Yes Assembly Unassembled Wheel Diameter 18 1/2 in Airflow @ 0.000 in SP 3 547 cfm Airflow @ 0.250 in SP 3 332 cfm Airflow @ 0.500 in SP 3 097 cfm Airflow @ 0.750 in SP 2 813 cfm Airflow @ 1.000 in SP 2 462 cfm Airflow @ 1.250 in SP 2 002 cfm Maximum Static Pressure 1 1/4 in wc Maximum Inlet Air Temperature 104 Degrees F Shaft Diameter 1 in Bearing Type Ball