**Stainless Steel Rotating Chimney Cowl Cap: The rings of this chimney cover are specially designed to overlap each other so that wind will not come down from the chimney, making the cover a perfect anti-settling solution. This pot will not let enter your room.The diameter of the base is suitable for most standard chimneys. **Principle Of Operation：the rings of this chimney cowl are specially designed and placed one over the other in a way that the wind cannot go down the chinmey, Hat designed to rotate with the action of the wind, so that the more the wind blows, the more the blades rotate, and the more powerful the air intake is from the inside out.Rotating hood for ventilation pipes, chimneys, and air extraction.thus making this cap a prefect anti downdraught solution. **Uses:Rotating hoods for ventilation ducts, chimneys and exhaust devices. The hood provides maximum protection without affecting the performance of the chimney.There is no noise when the roof ventilation fan rotates. The distance between the downwardly protruding slats is small enough to prevent rainwater from entering the ventilation system If you have any questions, please do not hesitate to contact us. Thank you for coming, wish you a happy life！