This 12-blade Outdoor Water Solutions Windmill Aeration System stands 27ft. tall to the top and can aerate ponds up to 2 or 3 acres in size with as little as 3–5 mph winds. The wind-driven system aerates a pond or lake from the bottom up, reducing algae, bacteria and odor, while adding oxygen and preventing pond stratification, which helps to reduce fish kills. Aeration also keeps ponds from freezing over in the winter, aiding waterfowl hunting. This system comes with 2 diffusers and a selector valve, so you can choose to use one or the other of the diffusers, or use them both at the same time. Complete system includes 24ft.H tower, windmill head, 100ft. of 1/2in. dia. poly tubing, 200ft. of 1/2in. weighted airline, 2 Airstone diffusers with 2 backflow valves, 2 airstone housing buckets, 2 duck decoys, and a 2-way selector valve. Adding tower hinges (not included) for ease of installation and maintenance is strongly recommended.