Function: 1 . Greenhouse window opener kit, adopts aluminum alloy material, with good durability and stability. 2 . When the temperature changes automatically, it can automatically open and close to prevent the greenhouse from overheating. 3. With springs and support rods to provide extra protection against wind damage. 4 . Can be directly clamped or screwed to the greenhouse frame, easy to install and use. 5 . Maintain an optimal growth temperature in the greenhouse and provide a suitable growing environment. Specification: Item Type: Window Opener Kit Material : Aluminum alloy Black colour Applications: Greenhouse, household Bearing weight: 14kg.31lb Opening force: 7kg to 15lb Closing force: 0.5kg to 1lb Product operating temperature: 17-25 Maximum opening temperature: 30 Maximum opening distance: approx. 45cm to 17.7in Weight: approx. 570g to 20.1oz Window Opener Size: Approx. 31.5cm to 12.4in Cylinder Size: Approx. 34cm to 13.4in Package List : 1 x Accessory Kit (12pcs) 1 x English Manual 1 x Opening windows 1x Cylinder 1 . Please allow 0-1 inch error due to manual measurement. 2 . Please take the real one as standard.