Aluminum Garden Tool Ventilation Of Greenhouse Agricultural Solar Heat Sensitive Automatic Vent Window Opener Double SpringSPECIFICATIONS Brand Name: NoEnName_Null Origin: Mainland China Model Number: 28987 Type: Solar Agricultural Greenhouses Choice: yes Features: Fully automatic greenhouse ventilation, prevent greenhouse overheating. Non electric, uses solar energy, open or close the greenhouse vents as temperature rises or drops. As the temperature changes automatically, maintains the best growing temperature and prevents your greenhouse from overheating. Can be