The iLIVING shutter exhaust fan is a must have for your home or business. Our shutter exhaust fan comes with 3 adjustable speeds and build-in thermostat is a must to have fan for cutting your cooling bills and improving comfort. It is perfect for removing excess heat, moisture, and unpleasant odors from home and commercial location, including garage, attic, restaurants, factories, warehouses, barns, and greenhouses. This fan features aluminum blades, OSHA compliant wire guards, and automatic louvers that open and close in tandem with the operation of the fan. The completely enclosed Class B motor is thermally protected and permanently lubricated. Build-in thermostat enables this fan to intelligently regulate the room temperature. It has a control temperature range of 32-130F, and a double terminals switch to bypass the thermostat allowing the fan to be always on. The fan comes fully assembled with 6 feet long, standard 3 plugs AC cable out of the box. No electrician required when plugged into an approved electrical outlet. The shutter fan comes in 8 different sizes: 10 inch-600CFM, 12 inch-800CFM, 14 inch-850CFM, 16 inch-1280CFM, 18 inch-1750CFM , 20 inch(2 speed)-3300CFM, 24 inch(2 Speed)-4200CFM and 30 inch(2 Speed)-5100CFM. Engineered in USA, UL listed.