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 dropsIncluding fittings & installation manualCan be clamped onto or screwed onto your greenhouse frameImportant notice:Do not use this opener anywhere the temperature exceed 50° (122F)Please your greenhouse window can be opened freely by at least 45cm (18inch) Do excessive loads by locking or covering windowDo not dismantle the cylinderThe opener CANNOT stop by manual. Greenhouse Window Opener Kit Color: silver + black Material: Aluminum Alloy Fully adjustable between 20 - 25 ° C (68 - 77 ° F) Maximum window opening: 45cm / 18 inch Size: 38 x 9.5 x 9.5 cm / 14.96 x 3.74 x 3.74 inch Package: 1* Automatic Window Opener Kit Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.