Description:Prevent greenhouse overheating.Ideal for your greenhouse window--opens and closes your greenhouse window.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.Can be clamped onto or screwed onto your greenhouse frame.Important notice: 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 excessive loads by locking or covering windowDo not dismantle the cylinder The opener CANNOT stop by manualSpecifications:Maximum window opening: 45cmMaximum opening temperature about: 30/86depending on adjustment and load Maximum opening weight: 7kg/15lbAdjustable open temperature range: 15- 25/60-77FSize: 38 x 9.5 x 9.5 cm / 14.96 x 3.74 x 3.74 inch (appr.)Package included:1 x Automatic window openerNote: Due to the upgrade of this item, the 11th part showed in manual is not included. Please take the real one as standard..