The manual air valve can accurately control the air flow rate and flow direction to ensure stable and efficient operation of the ventilation system. Whether it is a factory workshop, a commercial building, or residential fresh air system, it is necessary for its control over the circulation of the air. The main body is made of galvanized iron, which has strong anti-rust ability, can effectively resist moisture, acid and alkali corrosion, adapt to a variety of complex environments. The silicone seals are tightly fitted, which can greatly reduce air leakage and ensure stable operation of the ventilation system.