Selectable CFM and Continuous Run: speeds of 50-80-100 for effective ventilation and built-in continuous run technology to remove moisture and reduce the risk of mold or mildew in most full baths TRUE CFM: Installed exhaust fan will not lose CFM performance even with complicated ducting, unlike the competition. ENERGY STAR Certified & Meets ASHRAE 62.2 Quiet Performance: 0.4 / 0.9 / 1.2 Sones for quiet performance, enough sound to know your fan is on Adjustable low CFM setting allows precise adjustment to prevent over-ventilating and maximize energy efficiency Adjustable time delay sets how long fan will run on high speed before returning to a continuous lower speed ETL listed for use over bathtubs and showers when connected to GFCI protected branch circuit (ceiling installation only) Powerful enough for rooms up to 90 sq. ft. 4" oval duct connection for installation flexibility, allows for ceiling or wall mounting . Optional 4" oval to 3" round duct adapter sold separately (S1110515)