Blower Wheel Type Backward-Inclined Drive Type Belt Drive Includes Drive Package Yes Assembly Unassembled Wheel Diameter 27 in Airflow @ 0.250 in SP 12 856 cfm Airflow @ 0.500 in SP 12 606 cfm Airflow @ 0.750 in SP 12 356 cfm Airflow @ 1.000 in SP 12 106 cfm Airflow @ 1.250 in SP Not Applicable Airflow @ 1.500 in SP 11 599 cfm Airflow @ 2.000 in SP 11 076 cfm Airflow @ 2.500 in SP 10 526 cfm Airflow @ 3.000 in SP 9 935 cfm Airflow @ 3.500 in SP 9 218 cfm