Blower Wheel Type Backward-Inclined Drive Type Belt Drive Includes Drive Package Yes Assembly Unassembled Wheel Diameter 27 in Airflow @ 0.250 in SP 11 188 cfm Airflow @ 0.500 in SP 10 903 cfm Airflow @ 0.750 in SP 10 617 cfm Airflow @ 1.000 in SP 10 329 cfm Airflow @ 1.250 in SP Not Applicable Airflow @ 1.500 in SP 9 737 cfm Airflow @ 2.000 in SP 9 106 cfm Airflow @ 2.500 in SP 8 406 cfm Airflow @ 3.000 in SP 7 575 cfm Airflow @ 3.500 in SP 6 285 cfm