The window opener automatically opens and through the thermal induction of the temperature, maintains the best growing temperature. When the temperature changes, the vent opener automatically stretch or contract the vent. Auto-opening temperature range is adjustable from 15-25 degree centigrade by turning the cylinder. Features -Color: Silver -Material: Galvanized sheet, aluminum -Size: About 34.00X12.00X5.00cm/13.36X4.72X1.97inch - ventilation window opener in cannot be used in an environment where the temperature is higher than 50 degree centigrade. -The maximum height of the open window is about 45 -The window opener is made of materials, which is strong and sturdy. -It be installed easily onto your greenhouse frame, very simple and convenient. -Great for variety of occasions, garden, flower room, farm, botanical garden, railway and greenhouse. Package list: 1 x Automatic Vent Opener