Enhanced dual spring design delivers stronger thrust and higher load capacity than typical single‑spring models, allowing each automatic greenhouse vent opener to support up to 30lbs (15kg). This reliable structure improves stability in windy conditions and varied climates, making it suitable for a wide range of greenhouse roof vents and . galvanized steel sheet construction provides outstanding resistance and long service life,making these greenhouse window openers ideal for humid,high‑temperature environments. The smooth, uniform galvanized layer offers both strength and an attractive appearance, helping the vent opener resist deformation, rust, and everyday wear. Solar heat sensitive mechanism automatically opens and closes your greenhouse window according to temperature changes, operating effectively between 15℃ to 25℃ (60℉-77℉). By responding to solar heat, this automatic window opener helps maintain a balanced climate, preventing overheating while supporting healthy, consistent plant growth. Smart temperature and ventilation control lets you adjust indoor airflow for an optimal growing environment. The maximum window opening reaches about 45cm/17.72 inches, and the opening time can be manually fine‑tuned. This precise vent management helps regulate humidity and temperature, promoting robust plant health throughout the seasons. Easy installation with included clamps and screws allows you to quickly set up the greenhouse vent opener on most standard roof vents. For best results, place the black bar (cylinder rod) in the refrigerator for at least 5 minutes before assembly to it fully retracts, then mount securely to enjoy automatic, maintenance‑free ventilation., Manufacturer: Ounfhtrttk