100% brand new and high quality Fully automatic greenhouse ventilation Easy to fix with supplied clamps or screws No batteries or electricity required With automatic window openers, you can be sure of an even temperature in your greenhouse day and night. Allow thermostatic control of ventilation through the roof windows of your greenhouse Material: Aluminum alloy Color: Black Package Contents: 2 x Window Opener Cylinder Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in a little different from the real thing. The measurement allowed error is +/- 1-3 cm.