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, thus making this cap a prefect anti downdraught solution. This pot will not allow the fumes go down and enter your room. EXTENDED LIFESPAN：due to its stainless steel construction this Chimney top cover will last longer than regular steel caps. The lack of moving parts will increase its life and serviceability. Rotating hood：Chimney hood made of 304 stainless steel, very light and resistant to corrosion, heat and cold. It is installed easily and quickly to the extraction pipe. By not allowing the fumes go too fast out of the Chimney this flue cover creates an even combustion of the burning material thus not only saving you money and fuel but also keeping the warmth longer inside.