Janssens Automatic Roof Window Opener
For Royal or Junior Victorian Greenhouses: the black tube is filled with special paraffin oil - which expands when the temperature reached around 72º and the piston will push the window open up to about 14". When temperature falls a heavy spring pulls the window closed. No electricity needed!
- Fully automatic - no electricity needed!
- Opens to approx 14"
- Black color
For Royal or Junior Victorian Greenhouses