EXHAUST FAN, ASSEMBLED ASSEMBLED, BLADE DIAMETER 20 IN, BLADE MATERIAL ALUMINUM, DRIVE TYPE DIRECT DRIVE, DUCT DIAMETER 20 1/2 IN, EXHAUST AIRFLOW @ 0.000 IN SP 4,855 CFM, FRAME FINISH GALVANIZED, FRAME MATERIAL STEEL, GUARD TYPE NONE, INCLUDES DEHUMIDISTAT NO, MAXIMUM NOISE LEVEL 23 SONES