Louvered aluminum vent with a temperature-controlled wax cylinder. Can be adjusted to automatically open at approx. 65–75°F, effectively dispersing hot air from greenhouse peaks. Includes Poly Latch Wire for installation into greenhouse plastic, no framing required. Can be used manually with cylinder detached for winter growing, as ventilation is still important for disease prevention. Available in four sizes. NOTE: Vent may look different than pictured. These vents are intended for supplemental ventilation only. They are not the primary mechanism for temperature control in high tunnels.