ACDelco 10-4023 Diesel Exhaust Emissions Reduction (DEF) Fluid - 2.5 gal Meets GM Original Equipment specifications to be approved for use in GM vehicles as well as in non-GM diesel vehicles that have an SCR (Selective Catalytic Reduction) system to meet regulated NOx emissions High quality formula is made from high purity urea and deionized water. It contains no chemical additives or other components that could cause SCR system failure Includes vented nozzle(s) that make pouring easy by helping to prevent glugging Extra nozzles sold separately