Broan-NuTone 82W Humidity Sensing Wall Control, White Exclusive sensor humidity sensing technology responds to increases in humidity to automatically turn fan on before moisture forms on mirrors Relative humidity set point mode (50%-80% range to satisfy California requirements) Precise sensitivity adjustment can be set by user so fan works when homeowner wants it to regardless of climate or season User-adjustable automatic shutoff timer for customized run-time in different bathrooms and continuous ventilation mode operates fan for set minutes per hour to achieve targeted average cfm level and meet ashrae 62.2 requirements Compatible with any existing fan, and decorator-style design - with settings behind door - blends in with other controls and features led fan "on" indicator