Blower Wheel Type Backward-Inclined Drive Type Belt Drive Includes Drive Package Yes Assembly Unassembled Wheel Diameter 10 1/2 in Airflow @ 0.250 in SP 2 281 cfm Airflow @ 0.500 in SP 2 250 cfm Airflow @ 0.750 in SP 2 213 cfm Airflow @ 1.000 in SP 2 175 cfm Airflow @ 1.250 in SP 2 136 cfm Airflow @ 1.500 in SP 2 094 cfm Airflow @ 2.000 in SP 2 006 cfm Airflow @ 2.500 in SP 1 907 cfm Airflow @ 3.000 in SP 1 795 cfm Airflow @ 3.500 in SP 1 670 cfm Airflow @ 4.000 in SP 1 513 cfm