KOHLER Atmo 13-7/8-Inch X 13-7/8-Inch Bathroom Exhaust Fan With Light

Atmo 13-7/8-Inch X 13-7/8-Inch Bathroom Exhaust Fan With Light. Three fan control speed settings (100, 130, 150 CFM) with standard 6" (152 mm) air duct CFM will vary with 4" (102 mm) air duct. Lowest speed operates at a whisper-quiet 0.4 sones with standard 6" (152 mm) air duct and at 0.6 sones with 4" (102 mm) air duct. Fits standard bathroom exhaust fan cutouts to make upgrading easy. 6" to 4" duct reducer ensures airflow efficiency by creating connection between air duct openings of two different sizes. Environmentally friendly dimmable lighting capability saves energy and changes your bath’s lighting appeal. Requires dimmer light switch (sold separately)