This 12 Windmill aerator includes 100' Weighted Tubing and EPMD2 diffuser. Pumps 3 CFM of air in lowWinds and up to 4.5 CFM in 15+ MPH Wind. Effective in as little as 3-5 MPH Wind. Easy to assemble. Redesigned blades with rounded edges for better air flow. Large diaphragm and check valves for increased air flow. Patent-pending technology minimizes bearing fatigue and increases longevity. Can be located in an open area with tubing running to the pond. 72 diameter head has 12 blades. 18 gauge galvanized steel parts will last for years in all weather conditions.