For Small or Medium Rooms: Installation requires attic access, wiring and ducting to match 4'' duct size; Existing hole needs to be the same size or smaller than can size 7 7/8'' housing can and 9 1/2'' grille cover

Customizable Airflow: This ultra-slim, whisper quiet, Energy Star-certified fan features Pick-A-Flow technology that allows you to select your desired airflow from 70 or 90 CFM at the flip of a switch for your room size and usage needs