Universal Roof Vent Opener
It's very important that your greenhouse has proper ventilation. By adding this auto opener you roof vent(s) will open and close automatically. Powered by a special liquid inside the tube, the liquid expands when it gets warm and contracts when it gets cold.

Great when you away for a day or two. Have the peace of mind that your plants won't freeze or get too hot. Works on many roof vents. It does not work on Rion greenhouses. If you're unsure if it works on your greenhouse, call us and we'll let you know!