Features: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. Specifications:Replacement Greenhouse Window Opener CylinderTemperature range 15- 25/60-77FMaximum opening weight 7kg/15lbAdjustable length 33-45cmThis products need to be refrigerated before use it.Package:1 x Winder Opener CylinderNotes: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.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.