Controlled with a separate on-off switch or speed control; Permanently lubricated, thermally protected, plug-in motor; Motor assembly offers fast, easy "twist-lock" installation; Specially designed polymeric fan blade; Contemporary styled grille complements modern decor; Aluminum filter available (Purchase separately); Housing adjusts to fit walls from 4.5 IN to 9.5 IN thick; Rugged steel housing with modern profile on outer weather hood; Long-lasting electrically bonded epoxy coating can be painted to match outdoor styling; Built-in backdraft damper; 1 YR warranty