Blower Wheel Type Backward-Inclined Drive Type Belt Drive Includes Drive Package Yes Assembly Unassembled Wheel Diameter 18 1/4 in Airflow @ 0.250 in SP 6 445 cfm Airflow @ 0.500 in SP 6 293 cfm Airflow @ 0.750 in SP 6 136 cfm Airflow @ 1.000 in SP 5 972 cfm Airflow @ 1.250 in SP 5 800 cfm Airflow @ 1.500 in SP 5 621 cfm Airflow @ 2.000 in SP 5 235 cfm Airflow @ 2.500 in SP 4 795 cfm Airflow @ 3.000 in SP 4 224 cfm Airflow @ 3.500 in SP Not Applicable