1. Fully automatic greenhouse ventilation 2.Heat activated 3.Fully adjustable to open between 15-25 ℃ (60-77 ℉) 4.Suitable for windows up to 7kg( 15lbs ) 5.Easy fitting by clamps or screws provided<br><br>6.No batteries or electricity required 7. With SS spring. 8. With the automatic window openers, you can be sure of an even temperature in your greenhouse day and night. They allow thermostatic ventilation control through the roof windows of your greenhouse. 9. Replacement cylinders are available. Colour:black Material:aluminum alloy<br><br>Package Contents: 1 x Automatic Window Opener kit<br><br>Only the above package content, other products are not included. Note: Light reflection 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.