Glass Greenhouses -2 Pieces Stainless Steel Greenhouse Window Automatic Spring Opener Highlights generic brand 2 Pieces Stainless Steel Greenhouse Automatic Window Spring Opener Description: -Automatic Glasshouse Spring Opener solar heat sensing greenhouse window. -Made of superior stainless steel, sturdy, maximum opening load: 7kg / 15kg -Working principle: as the temperature changes automatically, thermal expansion and contraction, the black cylinder maintains the best growth temperature and prevents your greenhouse to overheat. -Solar powered, automatically open or close the greenhouse vents as the temperature rises or falls. - Energy saving and eco-friendly, no electricity needed. Specification: Material: Superior Stainless Steel Size: Approx. 38x10x5cm/14.96x3.94x1.97inch Maximum window opening: 45cm Maximum opening: 30° depending on setting and load - Single spring kit: Max opening weight load: 7 kg Adjustable open temperature range: 20 & deg; -25° / 68 -77F Package Include: 2 Pcs Greenhouse Window Opener Note: Please do not use the opener where the temperature will exceed 50° (122F). Please do not remove the cylinder, the opener cannot be stopped manually.