PLENUM FAN, WHEEL TYPE BACKWARD-CURVED, DRIVE TYPE BELT DRIVE, INCLUDES DRIVE PACKAGE YES, ASSEMBLY UNASSEMBLED, WHEEL DIAMETER 24 1/2 IN, AIRFLOW @ 0.000 IN SP 11,426 CFM, AIRFLOW @ 0.250 IN SP 11,265 CFM, AIRFLOW @ 0.500 IN SP 11,103 CFM, AIRFLOW @ 0.750 IN SP 10,941 CFM, AIRFLOW @ 1.000 IN SP 10,779 CFM, AIRFLOW @ 1.250 IN SP 10,617 CFM, AIRFLOW @ 1.500 IN SP 10,452 CFM, AIRFLOW @ 1.75 IN SP 10,255 CFM, AIRFLOW @ 2.000 IN SP 10,057 CFM, AIRFLO