Blower Wheel Type Forward-Curved Drive Type Belt Drive Includes Drive Package Yes Assembly Unassembled Wheel Diameter 18 1/4 in Airflow @ 0.250 in SP 3 780 cfm Airflow @ 0.375 in SP 3 530 cfm Airflow @ 0.500 in SP 3 255 cfm Airflow @ 0.750 in SP 2 090 cfm Airflow @ 1.000 in SP Not Applicable Airflow @ 1.250 in SP Not Applicable Airflow @ 1.500 in SP Not Applicable Airflow @ 2.000 in SP Not Applicable Airflow @ 2.500 in SP Not Applicable Airflow @ 3.000 in SP Not Applicable