The Automatic Vent Opener was designed to automatically control the temperature in all Palram - Canopia Greenhouses. As the air inside the greenhouse warms, the vent gradually opens to allow the correct amount of airflow into the greenhouse and closes when the optimal temperature is reached. The vent arm was designed with the use of natural wax that expands to push a piston, which raises the window, as the air gets warmer then contracts as it cools, closing with the use of a spring. The Automatic Vent Opener operates without the use of electricity. Opens roof vent window automatically around 68°F for air circulation, closes when the temperature cools. Opens gradually as the temperature rises. The operating temperature is slightly adjustable. Durable metal design with natural wax Smart-Lock connectors make installation quick and easy Works with Palram - Canopia Nature Series (Mythos, Hybrid, Essence), Snap & Grow, Glory, Americana, and Chalet greenhouses Window is not included 1 Year Limited Warranty