Blower Wheel Type Backward-Inclined Drive Type Belt Drive Includes Drive Package Yes Assembly Unassembled Wheel Diameter 30 in Airflow @ 0.250 in SP 16 321 cfm Airflow @ 0.500 in SP 16 020 cfm Airflow @ 0.750 in SP 15 720 cfm Airflow @ 1.000 in SP 15 419 cfm Airflow @ 1.250 in SP Not Applicable Airflow @ 1.500 in SP 14 812 cfm Airflow @ 2.000 in SP 14 188 cfm Airflow @ 2.500 in SP 13 536 cfm Airflow @ 3.000 in SP 12 843 cfm Airflow @ 3.500 in SP 12 100 cfm