Ceiling Ventilator Discharge Direction Horizontal and Vertical Duct Shape Rectangular Housing Material Steel Heater Without Heater Includes Automatic Backdraft Damper Mounting Location Ceiling Maximum Airflow 538 cfm Exhaust Airflow @ 0.100 in SP 520 cfm Exhaust Airflow @ 0.000 in SP 539 cfm Maximum Noise Level 3.3 sones Noise Level @ 0.100 in SP @ 5 ft 3 sones Number of Speeds Variable Overall Depth 12 1/4 in Overall Height 11 3/4 in Overall Width 21 1/2 in Lighted Without Light