Plenum Fan Wheel Type Backward-Curved Drive Type Belt Drive Includes Drive Package Yes Assembly Unassembled Wheel Diameter 22 in Airflow @ 0.250 in SP 3 517 cfm Airflow @ 0.500 in SP 2 992 cfm Airflow @ 0.750 in SP 2 254 cfm Maximum Inlet Air Temperature 104 Degrees F Shaft Diameter 1 1/8 in Bearing Type Ball Sound Level 6.5 sones @ 0.250 in SP and 5 ft Frame Material Galvanized Wheel Material Aluminum Inlet Diameter 13 1/2 in Rough Opening Height 30 in