Single/Double Spring KitFeatures: Prevent the greenhouse from overheating. Perfect for your greenhouse windows open and close your greenhouse Windows. With automatic temperature changes, maintain the optimal growth temperature and prevent your greenhouse from overheating. Non-electric, using solar power, opening and closing greenhouse vents as temperatures rise and fall. Can be clamped or screwed to the greenhouse frame. Opener RodFeatures: This is the replacement cylinder for the automatic window opener. High sensitivity, automatic response to weather changes, no need to stay near the greenhouse. Non-electric, using solar power, opening and closing greenhouse vents as temperatures rise and fall. Perfect for most greenhouses that automatically open or close Windows. It saves time and effort, and also provides better temperature conditions for the growth of plants. Specification: 100% brand new with high quality Style: A/B/C(Optional) Single/DoubleSpring KitSpecification: Material: Aluminum Alloy Fully adjustable between 20 - 25 C (68 - 77 F) Maximum window opening: 45cm / 18 inch Maximum opening weight: 7kg/15lb Size: Approx. 38x9.5x5cm / 15.0x3.7x2.0in Opener RodSpecification: Material: ABS Color: Black Temperature Range: 20-25 / 68-77 Size: Approx. 33 x 1.5cm / 12.99 x 0.59in Maximum Opening Distance: Approx. 45 cm / 18in Adjustable Length: Approx. 33-45cm/ 13-18in Application: For Under 14 Kg Window Package Included: (Optional) 1 xAutomatic Window Opener KitOR1 xWindow Opener Cylinder Note: Do not use this opener anywhere the temperature will exceed 50 (122F) Please ensure your greenhouse window can be opened freely by at least 45cm (18") Do not apply exceive loads by locking or covering window Do not dismantle the cylinder The opener can not stop by manual The colors may be a little difference for the different monitor display. Please check as much as poible to make sure the item is the one that you need. Please allow 0.5-1 inch difference due to manual measurement.(1inch=2.54cm)