FlexFlow(TM) technology, select between 50, 80 or 110 CFM, Quiet operation at , Powerful ventilation reduces humidity to quickly eliminate fogged mirrors and manage moisture, so your vision will always be clear and your surroundings will always be comfortable, Retrofit installations can be done entirely from the room-side - no attic access required. This means a faster, easier installation, so you can move on to something else, Flex DC fans reduce air leakage by up to 50% compared to competitive models, resulting in better home performance via blower door tests and reducing cold and warm air backdrafts