Dynaflux 929 Concentrated Defense with Ethylene Glycol, 2.5 Gallon. 929 provide year-round pump protection for water recirculators and closed loop cooling systems. Reduces the need for water fill maintenance by reducing water evaporation. The concentrated 929 formula protects from freezing to -30°F when not diluted. A dilution of 2 parts Defense 929 to one part water will protect to -10°F.