The Aeromat Mini is a passive Air Ventilator for installation in the upper Third of the window. The Room is Ventilated as the Indoor and Outdoor air pressures are Equalized (Pressure Differential). Normally, Air Flows from outside into the room. In Event of wind Pressure (E.G. Storm) The self-regulating Flow Control REDUCES an excessive Air Flow or draught indoors. You can also Open and Close the air inlet Cloning using the optional Turn Lock. The Aeromat Mini is besonders suitable for Apartments where the water Formation at the window and the Mold around the window is Due to Lack of ventilation. The Fan is used to achieve Constant Basic Ventilation. The Window Rabatte Fan Complies completely with DIN 1946 - 6 (Ventilation for dampness Protection). Aeromat can be used for Timber, PVC, Aluminium Windows and Portal Doors. Installation and operating instructions Manual: https://www.manualslib.com/manual/1176488/siegenia-aeromat-mini.html Protect your child from falling out the window by installing This Window Safety Lock: https://www.amazon.it/dp/b06 x vbl78 W if you have any questions about your purchase please contact us.