Universal, for greenhouse and cold frame applications.
Temperature-responsive opener for greenhouse windows and traditional cold frames. Can be adjusted to open between 60°F/16°C and 77°F/25°C. Extends to 18", lifts up to 15 lb. Made from corrosion resistant materials including aluminum and stainless steel. Quick-disconnect mounting bracket is especially useful when mounted on cold frames. Also appropriate for roof and wall vents.
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How it works: Vent openers do not require electricity. The opener has a metal cylinder containing a mineral wax which expands when heated. This pushes a piston that opens the vent. As the temperature cools, the wax 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.