Blower Wheel Type Backward-Inclined Drive Type Belt Drive Includes Drive Package Yes Assembly Unassembled Wheel Diameter 15 in Airflow @ 0.250 in SP 3 450 cfm Airflow @ 0.500 in SP 3 302 cfm Airflow @ 0.750 in SP 3 145 cfm Airflow @ 1.000 in SP 2 980 cfm Airflow @ 1.250 in SP 2 800 cfm Airflow @ 1.500 in SP 2 599 cfm Airflow @ 2.000 in SP Not Applicable Airflow @ 2.500 in SP Not Applicable Airflow @ 3.000 in SP Not Applicable Airflow @ 3.500 in SP Not Applicable