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 window Do not dismantle the cylinder The opener CANNOT stop by manual Specifications: Maximum window opening: 45cm Maximum opening about: 30° depending on adjustment and load Maximum opening weight: 7kg/15lb Adjustable open temperature range: 15°- 25°/60°-77F Size: 38 x 9.5 x 9.5 cm / 14.96 x 3.74 x 3.74 inch (appr.) Package included: 1 x Automatic window opener Note: Due to the upgrade of this item, the 11th part showed in manual is not included. Please take the real one as standard. 【PREMIUM QUALITY】The window opener is made of high quality aluminum alloy. Durable and rust resistant in damp environments Long service life. 【AUTO WINDOW OPENER】As the temperature changes automatically, maintains the best growing temperature and prevents your greenhouse from overheating. The automatically adjusted temperature is 20 to 25°C. Double spring mechanism protects against wind gusts, clamps to greenhouse bars , no drilling needed. 【EASY TO INSTALL】The Automatic vent opener is appropriated for most of the current garden greenhouses. It's equipped with screws, can be installed directly with clamps(not included) or screws, very simple and convenient. 【USE SOLAR ENERGY】Non electric, uses solar energy, open or close the greenhouse vents as temperature rises or drops. Ideal for your greenhouse window--opens and closes your greenhouse window. 【MAXIMUM OPENING】Maximum window opening is 45 cm and maxium opening temperature is 30°. It's suitable for most greenhouses.Easy to install,screw directly into polycarbonate panels, wood, or metal frames. It can also be clamped onto or screwed onto your greenhouse frame.