Plenum Fan Wheel Type Backward-Curved Drive Type Belt Drive Includes Drive Package Yes Assembly Unassembled Wheel Diameter 24 1/2 in Airflow @ 0.000 in SP 9 070 cfm Airflow @ 0.250 in SP 8 865 cfm Airflow @ 0.500 in SP 8 661 cfm Airflow @ 0.750 in SP 8 457 cfm Airflow @ 1.000 in SP 8 241 cfm Airflow @ 1.250 in SP 7 993 cfm Airflow @ 1.500 in SP 7 744 cfm Airflow @ 1.75 in SP 7 496 cfm Airflow @ 2.000 in SP 7 223 cfm Airflow @ 2.500 in SP 6 574 cfm Airflow @ 3.000 in SP 5 722 cfm