Alton | Thermofor Classic Roof Vent Auto Opener LED Lighting Roof vents with manual openers:

Roof vents with manual openers: Helps regulate airflow and temperature

The Janssens Side Window Fly Screen is an optional addition to your push open / tilt out side window in your Janssens greenhouse

The DuraBox won't rot

more open layout

Alton | Thermofor Classic Roof Vent Auto Opener LED Lighting Roof vents with manual openers:The Thermofor Classic Roof Auto Opener is a simple, reliable way to keep your Alton greenhouse properly ventilated, without any manual effort. Designed specifically for Alton greenhouse roof vents, it uses a heat sensitive, oil filled piston that automatically opens the vent as temperatures rise, helping create a healthier growing environment for your plants. As the greenhouse warms, the piston expands and gently lifts the vent. When temperatures