WhisperGreen Select is a ground-breaking IAQ solution that is revolutionizing the ventilation fan industry with a new set of features that enable customization and easier installation. To the builder and professional installer, Panasonic continues to be the innovation leader with high performance ventilation solutions that are built to last. WhisperGreen Select's unique design and superior energy efficiency are achieved through engineering expertise, provided by a company who sets the standard for quality and value. WhisperGreen Select features the same revolutionary DC motor that comes with our WhisperGreen line of products. With built-in SmartFlow technology, WhisperGreen Select is designed to perform as rated. When the fan faces static pressure, its speed is automatically increased to ensure optimal CFM output. This feature provides peace of mind, as the installer doesn't have to worry about compromising the fan's performance. ASHRAE, ENERGY STAR, LEED for Homes, and HVI have set the industry standard for performance measurement at .25" w.g. The WhisperGreen Select fans not only provide powerful CFM output at .25" w.g., but our sones have also been certified at .25" w.g. so they are quiet under pressure and after installation. Integrated dual 4" or 6" duct adaptor (up to 110 CFM models) .Built-in metal flange provides blocking for penetrations through drywall as an air barrier, and assists with the decrease in leakage in the building envelope during blower door testing. WhisperGreen Select fan/light models feature a contemporary flush mount grille that incorporates Two 7W self-ballasted GU24 base LED lamps. Panasonic's advanced LED technology lasts 5 times longer and is 75% more efficient than incandescent lamps and lasts at least 35 times longer. Ingeniously designed installation bracket provides flexible, fast and secure installation for all your new construction or renovation projects . 6 year warranty on DC motor, 5 years on LED, 3 years on parts.