Blower Wheel Type Radial Drive Type Belt Drive Includes Drive Package Yes Assembly Unassembled Wheel Diameter 33 in Airflow @ 2.500 in SP Not Applicable Airflow @ 4.000 in SP 12 304 cfm Airflow @ 5.000 in SP 11 329 cfm Airflow @ 6.000 in SP 10 352 cfm Airflow @ 7.000 in SP 9 381 cfm Airflow @ 8.000 in SP 8 401 cfm Airflow @ 9.000 in SP 7 320 cfm Airflow @ 10.00 in SP Not Applicable Airflow @ 11.00 in SP Not Applicable