Blower Wheel Type Forward-Curved Drive Type Belt Drive Includes Drive Package Yes Assembly Unassembled Wheel Diameter 20 in Airflow @ 0.125 in SP 7 211 cfm Airflow @ 0.250 in SP 6 911 cfm Airflow @ 0.375 in SP 6 622 cfm Airflow @ 0.500 in SP 6 334 cfm Airflow @ 0.750 in SP 5 732 cfm Airflow @ 1.000 in SP 5 009 cfm Airflow @ 1.250 in SP Not Applicable Airflow @ 1.500 in SP Not Applicable Airflow @ 2.000 in SP Not Applicable Airflow @ 2.500 in SP Not Applicable