1. The exterior hood grille is used as an exterior ventilation grille to cover ventilation ducts. It can be installed using dowels and screws. Check valves are universally available for all common round ventilation ducts and hoses according to DIN EN1506. Stainless steel is weather- and corrosion-resistant.2. 150 The ventilation grille is mounted on the outer wall of the exhaust air system. When the fan stops, the louver closes automatically, preventing the entry of cold air and keeping out dust, insects and other objects. Due to the ease of movement, the damper can be opened at very low pressure and is therefore also known as a floating damper.3. For hoods, workshops, cellars, tumble dryers etc. The typical rattling sound should be noted when installed near residential areas.4. The choice of amateurs and professionals. Easy to install with standard tools. Insert the vent damper into the vent pipe or hose and secure it to the wall with the screws supplied. Secure the grommet to the vent pipe for optimal fastening.