Purple Ice Coolant Additive is a high performance, synthetic, radiator coolant additive. It reduces engine heat by reducing the surface tension of the radiator fluids for improved heat transfer. Purple Ice fosters optimum coolant flow by helping to prevent formation of scale deposits in the radiator. It also lubricates the water pump seals. Purple Ice should always be used in conjunction with antifreeze in regions where freezing temperatures occur. Purple Ice is compatible with traditional ethylene glycol antifreeze (green) and GM Dex-Cool® antifreeze. Comes in a 16 oz. bottle.