Panasonic FV-08VKM2 WhisperGreen 80 CFM Premium Ceiling Mounted Continuous and Spot Ventilation Fan with SmartAction Motion Sensor Incorporates a totally enclosed DC motor designed for extremely quiet, energy-efficient operation SmartFlow Optimum CFM Technology automatically increases the fan's speed to ensure that the desired CFM is actually achieved CustomVent Variable Speed Control allows the fan to run continuously at a pre-set lower level of 0-70 CFM SmartAction motion sensor automatically activates whenever someone enters or leaves the room Can be elevated to a maximum of 80 CFM when the switch is turned on