QUIET, CLEAN AIR: At less than .3 sones, this fan operates just as loud as a whisper as it increases your air quality by eliminating humidity, mold, mildew, and other air pollutants from any room. LONG LIFE, GUARANTEED: Panasonic ventilation fans use less energy to move larger volumes of air. Less energy leads to less overheating and motor failure, saving you on repair costs. Included 6-year warranty on motor and 3-year warranty on parts. EASY-TO-INSTALL: Works with 4" and 6" ducts for flexibility in duct layout and design. Flex-Z Fast installation bracket is ideal for positioning the fan exactly where you want it. PLUG-N-PLAY: Customize your fan with up to three accessories, including the Multi-Speed module, SmartAction Motion Sensor, Condensation Sensor, or NiteGlo LED night light. CODE COMPLIANT: This product is ENERGY STAR certified and complies with ASHRAE 62.2, LEED, CALGreen, California Title 24, and WA codes and standards.