Description of the product function: The manual control of the roof ventilation exchanges the air in your motorhome or caravan within minutes. It removes cooking smoke and unpleasant aromas from the bathroom and lets you breathe fresh outside air. Breathe in natural, fresh outside air to make your living space more comfortable. NOTE: Installation instructions are NOT included Professional installation is highly recommended It is recommended to use a neutral structural glue for installation to avoid the bad combination of acidic and alkaline glue which can lead to bad chemical reactions like corrosion and glue cracks.