Plenum Fan Wheel Type Backward-Curved Drive Type Belt Drive Includes Drive Package Yes Assembly Unassembled Wheel Diameter 15 in Airflow @ 0.250 in SP 1 678 cfm Airflow @ 0.500 in SP 1 445 cfm Airflow @ 0.750 in SP 1 133 cfm Maximum Inlet Air Temperature 104 Degrees F Shaft Diameter 1 in Bearing Type Ball Sound Level 8.7 sones @ 0.250 in SP and 5 ft Frame Material Galvanized Wheel Material Aluminum Inlet Diameter 9 1/2 in Rough Opening Height 18 in