Tubeaxial Fan Drive Type Direct Drive Includes Drive Package Yes Includes Motor Yes Blade Diameter 18 in Nameplate Voltage 115V AC Phase 1 Motor Horsepower 1/2 hp Airflow @ 0.000 in SP 3 938 cfm Maximum Noise Level @ 5 Feet 25 sones Assembly Assembled For Air Type Clean Air Blade Material Aluminum Housing Material Steel Number of Blades 6 Number of Speeds 2 Motor Enclosure Totally Enclosed Air Over Standards AMCA Sound and Air UL Listed Bolt Circle Diameter 19 7/8 in