About this item This is a replacement cylinder for automatic window opener. Deal for your greenhouse window–opens and closes your greenhouse window. Great for most greenhouse to open or close window automatically. Adjustable for different opening heights and mountable two different ways, taking up as little space as possible within your greenhouse. High sensitive, automatic respond to weather changes, so you don’t need to stay near the greenhouse. As the temperature changes automatically, maintains the best growing temperature and prevents your greenhouse from overheating. Non electric, uses solar energy, open or close the greenhouse vents as temperature rises or drops. Window opener for greenhouse can time saving, also can supply a better temperature condition of plant’s growth.