Humidity Sensing Collection 80 CFM Humidity Sensing Exhaust Fan Air King's Humidity Sensing fans provide the perfect solution for areas prone to sudden increases in humidity levels such as bathrooms. Incorporating a built in humidistat, the fan senses the humidity level of the room and activates once the preset humidity level has been reached, remaining on until the humidity is once again below the preset level. Each fan operates at 80 CFM with an extremely low sound level and features a contoured grill that virtually disappears into the ceiling, creating a very low impact experience with big results. Once you install this fan, you'll hardly hear it at work, but you'll certainly see and feel the results. Features: Single Speed Operation ENERGY STAR Qualified California Title 24 Compliant Easy to Install Using the Included Adjustable Hanging Brackets UL Listed for Installation Over a Top or Shower on a GFCI Circuit Plastic Damper Protects Against Back Drafts and Ensures Quiet Operation 4" Round Duct Connector Specifications: Grille Dimensions: 11" x 13-3/4" Duct Size: 4" CFM: 80 Housing Length: 10-7/8" Housing Width: 9-3/8" Housing Depth: 7-7/8" Over the forty years Air King has been in business, they have developed something of a reputation for manufacturing quality ventilation products, offering products at a good value, and providing excellent service for their products. Air King believes that a home is more than just a house, it is a sanctuary from the busy world, so shouldn't it be comfortable as well? Their mission is to make homes healthier, more comfortable, and more convenient, and they have delivered for over 40-years.