This rotating cowl has even more advantages compared to a draught-inducing rain cowl. For example, this cowl will create even more draught in the duct due to its rotating action. Because it is oil-layered, its lifespan is very long. We recommend using this product for ducts of 8 meters or longer. If the cowl receives too much heat because it is placed too close to the stove, this will cause problems. Includes clamp band.