Features:Perfect 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. Please make sure your greenhouse window can be opened freely by at least 45cm (18").Specifications:Greenhouse Window Opener Kit Maximum window opening 45cmMaximum opening about 30°, depending on adjustment and loadMaximum opening weight 7kg/15lbAdjustable open temperature range 15°- 25°/60°-77FPackage:1# Automatic Window Opener Kit / Replacement Greenhouse Window Opener Cylinder (You can choose what you want)Notes:Do not use this opener anywhere the temperature will exceed 50° (122F) Please make sure your greenhouse window can be opened freely by at least 45cm (18") Do not apply excessive loads by locking or covering window Do not dismantle the cylinder The opener CANNOT stop by manual Monitors are not calibrated same, item color displayed in photos may be showing slightly different from the real object. Please take the real one as standard.