Welcome to use Chimney Cowl Cap feature: Rotating hoods for ventilation pipes, chimneys and exhaust. Made of 304 stainless steel, it is very lightweight and weatherproof. It can be easily and quickly installed on the extraction tube. The hat is designed to rotate under the action of the wind, so the more wind blows, the more times the blades rotate, and the more powerful the air intake from the inside to the outside. It prevents strong wind from entering the inside of pipes, chimneys, stoves, etc., thereby avoiding the adverse effects of smoky houses. Name:Chimney Cowl Cap [Material]: Thick 304 stainless steel [Features]: Zero energy consumption, no rust, no rain [Working principle]: Use the air convection caused by natural wind and indoor and outdoor temperature difference to drive the water turbine to rotate, thereby using centrifugal force and negative pressure effect to discharge the old indoor air. [Applicable]; industrial plant, breeding farm, residential flue, etc. Air volume: depends on roof wind Category: 110mm [304 Material Thickening Product] Send Clip 160mm [304 material thickened product] clip delivery 200mm [304 material thickened product] clip delivery 250mm [304 material thickened product] clip delivery [Tips]: If you have any questions, you can contact us by email, and we will solve it for you within 24 hours.