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 16 486 cfm Airflow @ 0.250 in SP 16 284 cfm Airflow @ 0.500 in SP 16 082 cfm Airflow @ 0.750 in SP 15 880 cfm Airflow @ 1.000 in SP 15 678 cfm Airflow @ 1.250 in SP 15 476 cfm Airflow @ 1.500 in SP 15 267 cfm Airflow @ 1.75 in SP 15 047 cfm Airflow @ 2.000 in SP 14 827 cfm Airflow @ 2.500 in SP 14 387 cfm