Windmill Aeration Systems are perfect for ponds where existing electric is not available or is too costly to run to the pond site. Each Windmill Aeration System is equipped with a tower, 18 gauge galvanized steel blade and tail assembly, compressor, airline and diffuser stone. A self-governing head is included on each system to protect the unit from high winds. All systems have a 5 year manufacturer's warranty on the compressor, bearings, and cams. Windmill Aeration Systems ship via motor freight.