Antifrogen® N is a liquid, tinted pale yellow, for use as a heat transfer medium in closed hot water heating systems, heat pumps and as cooling brine in industrial refrigeration equipment. Antifrogen® N is not suitable for the use in food or pharmaceutical applications. Antifrogen® N is inhibited without the use of nitrites-, amines-, borates-, silicates- and phosphates. The optimisation of the corrosion inhibition system was performed without the use of CMR-substances (cancerogenic, mutagenic, reprotoxic).