EXT external mount duct fans are the perfect solution when space restrictions prevent the use of in-line duct fans. Ventilate tight spaces such as basement kitchens, laundry rooms, basement bathrooms, attic mounting, crawl spaces, high rise buildings, apartments and much more with the external mount EXT fan. These fans provide a simple through-the-wall solution, and can be sidewall mounted on the exterior of a building to allow for easy access to the fan. EXT fans utilize quiet and energy efficient external rotor motors. EXT fans are available in three standard duct sizes: 4", 6" or 8", with airflow's ranging from 118 cfm to 420 cfm.