This Vitavia Automatic Roof Vent Opener 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.
This Vitavia Automatic Roof Vent Opener 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.