Specifications:This very smart autovent uses energy from the sun and surrounding air.Non Electric, uses solar energy, open or close the greenhouse vents as temperature rises or drops.This opener will automatically open and shut your greenhouse window to maintain the best growing temperature and preventing your greenhouse from overheating.Type: Automatic Window OpenerMaterial: Aluminium AlloyFeatures: Durable, Automatic, Easy to UseNotes:Do not use this opener anywhere the temperature will exceed 60 degree (140f).Please ensure your greenhouse window can be opened freely by at least 45cm (18").Get the very best from your greenhouse plants and veggies - dont leave it to chance.Due to the light and screen setting difference, the items color may be slightly different from the pictures. Package Includes:1 x Automatic Window Opener1 Set of Screws