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 10 386 cfm Airflow @ 0.250 in SP 10 208 cfm Airflow @ 0.500 in SP 10 030 cfm Airflow @ 0.750 in SP 9 852 cfm Airflow @ 1.000 in SP 9 673 cfm Airflow @ 1.250 in SP 9 491 cfm Airflow @ 1.500 in SP 9 274 cfm Airflow @ 1.75 in SP 9 057 cfm Airflow @ 2.000 in SP 8 839 cfm Airflow @ 2.500 in SP 8 405 cfm