Automatically opens and closes the roof vent/window when temperature changes. The opener has a metal cylinder containing a mineral which expands when heated. This pushes a piston that opens the vent. As the temperature cools, the mineral shrinks and a spring closes the vent and resets the piston. The opening and closing of the vent is gradual allowing just the right amount of air flow for cooling. Rion Automatic Roof Window Opener Fits Roof Windows/Vents for all Hobby Gardener Series HG-8, HR-12, HG-16, HG-20, HG-24 greenhouses, all Green Giant greenhouses, and all Prestige greenhouses.
- Assembled Dimension: 11 in. W x 2 in. D x 2 in. H
- Solar Powered, Heat Activated
- Easy to Install
- Protect your plants from over heat exposure
- Openers close vents automatically at night to retain heat