This top quality autovent which automatically opens and closes your greenhouse windows comes with a 2 year warranty. It works using the power of the sun so no electricity is needed. Perfect for letting the heat out of your greenhouse and when cool, keeping it in. You can set the device to automatically start opening between 17°C – 25°C depending on the setup. Made from Aluminium zinc coated steel. Has an opening force of 7kg. Maximum opening at 30°C.Maximum opening approx 45cm depending on adjustment and load. Full instructions provided. This product comes with a 2 year warranty.