Blower Wheel Type Backward-Inclined Drive Type Belt Drive Includes Drive Package Yes Assembly Unassembled Wheel Diameter 12 1/4 in Airflow @ 0.250 in SP 2 365 cfm Airflow @ 0.500 in SP 2 274 cfm Airflow @ 0.750 in SP 2 181 cfm Airflow @ 1.000 in SP 2 081 cfm Airflow @ 1.250 in SP 1 972 cfm Airflow @ 1.500 in SP 1 851 cfm Airflow @ 2.000 in SP 1 503 cfm Airflow @ 2.500 in SP Not Applicable Airflow @ 3.000 in SP Not Applicable Airflow @ 3.500 in SP Not Applicable