Unique modular design - Choose from four patented, optional modules to customize airflow and enhance indoor air quality for any space.;Pre-installed Multi-Speed Airflow Selector: provides the unique ability to select your required airflow, 30 to 110 CFM, with the simple flip of a switch;Integrated 6” to 4" reducer: Two duct adapter size options enhances installation options;Increased Energy Efficiency – Panasonic’s superior performance of 0.5” exceeds the industry standard set by ASHRAE and Energy Star;Designer Grille Options - Sharper, cleaner lines on the traditional grille and two new architectural grille designs for a more elegant appeal ;Expanded True Flow Performance - The only residential vent fan series with a combination of certified CFM performance at 0.5 w.g. and low sone levels;Optional Wi-Fi Control Module – Enables two-way communication between our ventilation products. Use this with a standalone fan or combine with an Indoor Air Quality healthy home system