Galvanized Windmill Aerator System Solar Double long: 4' x 20' Personalized Tailfin Logo:No Double long: 4' x 20' (qty 2 dock tops 4' x 8' Gangway This allows our units to pump up to 4 The Wind Driven Aeration Systems offer:“BalCam II” technology minimizes bearing fatigue with new Stainless Steel componentsPatent pending new designFast & Easy AssemblyManufactured with high quality 18 gauge galvanized steelNewly redesigned blades and front dome assembly for better air flowSelf governing head to protect the unit in high windsNew secure locking mechanism that attaches the windmill head to shaftLarger check valves and upgraded ½” airline to handle the increased air that is producedHigh Air Output – 3