The Broan Motordor™ Through Wall Utility Fan features steel housing that includes a foam-insulated door for energy efficiency. A separate motor opens the door when the fan is turned on, and closes it when the fan is off, saving valuable energy. The fan is designed for rooms up to 360 square feet and has a permanently lubricated, termally protected, plug-in motor. The housing adjusts to fit walls from 5-1/2" to 9-7/8" thick and is finished in a rugged black epoxy paint. The white polymeric grille has a contemporary style and can be painted to match any décor. Optional aluminum filters and control switches are available separately.