Plenum Fan Wheel Type Backward-Curved Drive Type Belt Drive Includes Drive Package Yes Assembly Unassembled Wheel Diameter 27 3/8 in Airflow @ 0.000 in SP 14 403 cfm Airflow @ 0.250 in SP 14 172 cfm Airflow @ 0.500 in SP 13 941 cfm Airflow @ 0.750 in SP 13 709 cfm Airflow @ 1.000 in SP 13 478 cfm Airflow @ 1.250 in SP 13 232 cfm Airflow @ 1.500 in SP 12 980 cfm Airflow @ 1.75 in SP 12 728 cfm Airflow @ 2.000 in SP 12 476 cfm Airflow @ 2.500 in SP 11 851 cfm