Alton | Thermofor Roof Vent Opener Piston Replacement Coconut peat block Its extra-wide double doors and

Its extra-wide double doors and low threshold entry make it easy to maneuver wheelbarrows

match the light to your tent size and aim for strong

Elegant Design Meets Everyday Function

Its understated and timeless look will compliment your backyard

Alton | Thermofor Roof Vent Opener Piston Replacement Coconut peat block Its extra-wide double doors andThe Thermofor Long Piston Replacement is a direct replacement cylinder designed for Thermofor automatic roof vent openers used in Alton greenhouses. If your current opener is no longer responding properly to temperature changes, replacing the piston is a simple way to restore reliable, automatic ventilation. This heat sensitive cylinder contains a wax core that expands as temperatures rise and contracts as they cool, driving the vent to open and close