Wiwir Auto Vent Opener Solar Heat Sensitive Automatic Greenhouse Window Opener Auto Vent Kit for Garden Greenhouses Roof Ventilation Lifts 30 Lbs(Double Spring Vent Opener)

??Premium Quality?-- This double spring Automatic Window Opener is made of quality built anodised aluminium.The paint spraying aluminum frame looks more lustrous, durable and rust-proof.The thicker and stronger material with two springs type, suitable for windy mountain area, resist wind twist. ??Greenhouse Automatic Vent Opener?-- As the temperature changes,This double spring auto thermo for window will automatically open and close your garden greenhouse vent to maintains the best growing temperature and prevents your greenhouse from overheating. ??Environmental friendly?-- Non electric, uses solar energy,open or close the greenhouse window as temperature rises or drops. This solar heat sensitive auto vent opener can lift up to 15 lbs. The cylinder closes well before deep freezing and opens again without problem. ??Working Conditions?--Start opening at 15°C-25°C (59-77°F);Fully open temperature at 30° (86°F) or above;Full opening distance :45 cm (18 inches).The greenhouse automatic roof vent opener kit will shut down completely when the temperature drops to bellow 59°F (15°C).Up to Load Capacity:7-15kgs(15-33lbs). ??Warm Tips?-- Do not use this automatic roof vent Opener lifts anywhere the temperature will exceed 45° (122F).