With a telescopic valve, you get a complete solution for ventilation in your home. A complete valve with wall penetration and insect screen. External white louvre grill, internal white valve. Note during installation: It is best to install telescopic valves in the outer walls - approx. 100 mm from ceiling. There should be two valves per room, depending on the size of the room. The valves must always be placed opposite each other so that the air circulation proceeds effortlessly. If possible, the valves should be placed on the west and east sides of the house, since the wind in Denmark mainly comes from the west.