The ENERGY STAR« Qualified Quiet Zone Exhaust Fan provides 50 CFM of cost effective and energy efficient ventilation at 0.5 Sones. It features a 4" round duct connector with spring loaded aluminum damper protects against back drafts to ensure quiet operation. It installs easily using the adjustable hanging brackets and the side access panel allows the fan to be wired without removing the interior components. Listed for installation over a tub or shower on a GFCI circuit.