Description: Prevent overheating of the greenhouse. 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, opens or closes greenhouse vents as the temperature rises or falls. Can be fixed or screwed to your greenhouse frame. Important Notice: Do not use this opener anywhere the temperature will exceed 50 ° (122F) Please make sure your greenhouse window can be freely opened by at least 45cm (18 ") Do not apply excessive loads by locking or covering the window Do not dismantle the cylinder, the opener cannot be stopped by manual Features: Maximum window opening: 45cm Maximum opening approx .: 30 ° Depending on the setting and the load maximum opening weight: 7kg / 15lb Adjustable open temperature range: 15 ° - 25 ° / 60 ° -77F Size: 38x9.5x9.5cm / 14.96x3.74x3.74 inch (appr.) Package included: 1 x Double Spring Window Opener