Working principle Have started up after the motor-driven fan airflow, the air supply lines, the shutter open automatically when the shutter closure stands. Indoor air pollution from thermal ventilation will naturally flow into the fresh air. (Applicable to vertical suction ventilation rooms, with chicken coop and greenhouse flowers Greenhouse) Characteristics The fan features big wind quantity, low noise, low energy consumption, smooth running, long life, elegant appearance and simple installation and so on. Click: 7