Window opener-- non electric, uses solar energy, open or close the greenhouse vents as temperature rises or drops.
Greenhouse auto vent openers-- thicker and stronger steel material, suitable for windy mountain area, resist wind.
Greenhouse vent window opener-- as the temperature changes automatically, maintains the best growing temperature and prevents your greenhouse from overheating.
Greenhouse ventilation opener-- solar heat design, it can open and close automatically.
Car tool-- high , automatic respond to weather changes, so you dont need to stay near the greenhouse. solar heat window opener