Blower Wheel Type Backward-Inclined Drive Type Belt Drive Includes Drive Package Yes Assembly Unassembled Wheel Diameter 20 in Airflow @ 0.250 in SP 7 107 cfm Airflow @ 0.500 in SP 6 923 cfm Airflow @ 0.750 in SP 6 728 cfm Airflow @ 1.000 in SP 6 520 cfm Airflow @ 1.250 in SP 6 296 cfm Airflow @ 1.500 in SP 6 054 cfm Airflow @ 2.000 in SP 5 495 cfm Airflow @ 2.500 in SP 4 776 cfm Airflow @ 3.000 in SP 3 600 cfm Airflow @ 3.500 in SP Not Applicable