About this item Temperature Range : Temperature range 15°- 25°/60°-77F. Solar Energy : Non-electric, adopted solar energy, open or close the greenhouse vents as temperature rises or drops. More Durable : This automatic greenhouse window opener cylinder made of quality material, durable, solid and convenient to use. For Most Greenhouses : As the temperature changes automatically, maintains the best growing temperature and prevents your greenhouse from overheating. Ideal for your greenhouse window. Note : Do not use this opener cylinder anywhere the temperature will exceed 50° (122F).