Is a corrosion inhibitor for brake fluid. It is compatible with DOT 3, 4, and 5 brake fluids, but is especially effective in silicon based brake fluids, such as DOT 5. M-408 dramatically improves corrosion protection of brake systems and does not adversely affect other properties of DOT-5 brake fluid, including flammability, high and low temperature serviceability, dry and wet boiling points, and compressibility. M-408 is very economical. When added to DOT-5 brake fluid, at a concentration level of 1-1.5% by weight, it provides corrosion protection for ferrous and yellow metals in conditions of high humidity and elevated temperatures.