PLENUM FAN, WHEEL TYPE BACKWARD-CURVED, DRIVE TYPE BELT DRIVE, INCLUDES DRIVE PACKAGE YES, ASSEMBLY UNASSEMBLED, WHEEL DIAMETER 15 IN, AIRFLOW @ 0.250 IN SP 1,873 CFM, AIRFLOW @ 0.500 IN SP 1,682 CFM, AIRFLOW @ 0.750 IN SP 1,430 CFM, MAXIMUM INLET AIR TEMPERATURE 104 DEGREES F, SHAFT DIAMETER 1 IN, BEARING TYPE BALL, SOUND LEVEL 10.4 SONES @ 0.250 IN SP AND 5 FT, FRAME MATERIAL GALVANIZED, WHEEL MATERIAL ALUMINUM, INLET DIAMETER 9 1/2 IN, ROUGH O