"This roof vent features a manual control system that allows you to completely refresh the air inside your motorhome or caravan in just a matter of minutes. It is highly effective at clearing out cooking smoke and eliminating unpleasant odors from the bathroom area. By actively circulating the air, you can ensure that your living space remains pleasant and free from stale or stuffy conditions. - Ventryn 14"" 12V Motorhome Skylight Fan with 4 LEDs - Camper Roof Vent in White"