Alton Thermofor Classic Roof Auto Opener

The Thermofor Classic Roof Auto Opener automatically opens and closes your Alton greenhouse roof vent based on temperature changes, helping improve airflow and prevent overheating. Featuring a heat-sensitive oil-filled piston, adjustable operating temperatures from 59°F to 77°F, and no need for electricity or batteries, this easy-to-install opener provides reliable, low-maintenance greenhouse ventilation.