In-Line Duct Blower Wheel Type Backward-Inclined Drive Type Belt Drive Includes Drive Package Yes Assembly Unassembled Wheel Diameter 18 in Airflow @ 0.000 in SP 5 894 cfm Airflow @ 0.125 in SP 5 790 cfm Airflow @ 0.250 in SP 5 686 cfm Airflow @ 0.375 in SP 5 577 cfm Airflow @ 0.500 in SP 5 463 cfm Airflow @ 0.750 in SP 5 236 cfm Airflow @ 1.000 in SP 4 964 cfm Airflow @ 1.250 in SP 4 662 cfm Airflow @ 1.500 in SP 4 298 cfm Airflow @ 2.000 in SP 3 106 cfm