Improve fuel economy by up to 5% while simultaneously reducing exhaust emissions with BlueDEF® Diesel Exhaust Fluid. This nontoxic solution is made from 67.5% purified water and 32.5% ultra pure automotive grade urea. While BlueDEF® is not a fuel additive, once injected into the exhaust stream and passed over a catalyst BlueDEF® helps convert NOx into nitrogen gas and water vapor – two harmless and natural components of the air we breathe. Stable, colorless and odorless BlueDEF® meets ISO Standards 22241 for purity and composition and is an American Petroleum Institute (API) certified diesel exhaust fluid, the highest quality and safety standards in place to ensure optimum SCR performance.