Assembled Whole House Fans • Mount: horizontal Thermally protected, 2-speed motors 115V/60 Hz Preassembled wood frameEffectively cool and ventilate an entire home by removing hot, humid air through the attic and drawing in cooler air from outside. Gasket between the venturi and plenum box reduces noise. All models include 2-speed wall switch with 12-hr. timer.Fans are UL and C-UL Listed.Heavy Duty Belt Drive and Direct DrivePainted steel housing. Belt drive models have automatic belt tensioning system which eliminates manual belt adjustment.