This Vitavia Univent Autovent for IDA Lean to's is filled with wax, when the wax reaches a certain temperature it opens your greenhouse roof vent. Once the wax cools and solidifies the vent closes to keep the heat inside your greenhouse.
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This Vitavia Univent Autovent for IDA Lean to's is filled with wax, when the wax reaches a certain temperature it opens your greenhouse roof vent. Once the wax cools and solidifies the vent closes to keep the heat inside your greenhouse.