Blower Wheel Type Backward-Inclined Drive Type Belt Drive Includes Drive Package Yes Assembly Unassembled Wheel Diameter 20 in Airflow @ 0.250 in SP 9 397 cfm Airflow @ 0.500 in SP 9 262 cfm Airflow @ 0.750 in SP 9 122 cfm Airflow @ 1.000 in SP 8 977 cfm Airflow @ 1.250 in SP 8 827 cfm Airflow @ 1.500 in SP 8 671 cfm Airflow @ 2.000 in SP 8 339 cfm Airflow @ 2.500 in SP 7 976 cfm Airflow @ 3.000 in SP 7 574 cfm Airflow @ 3.500 in SP Not Applicable