Sierra, Gallon, Antifreeze, Non-Toxic Propylene Glycol, Does Not Contain Poisonous Ethylene Glycol Making Sierra Safer For Pets, Children & The Environment, Formulated With Pg Rather Than Ethylene Glycol, Less Toxic, Provides Excellent Freeze Up & Boil Over Protection & Outstanding Corrosion Protection While Maintaining Heat Transfer Properties, Helps Prevent Accidental Poisoning Of Pets & Wildlife.