HD Expert Diesel Exhaust Fluid (DEF) is suitable for heavy-duty vehicles equipped with Selective Catalytic Reduction (SCR) technology and is engineered to maximize your diesel-powered vehicle’s performance while reducing harmful NOx emissions from diesel engines. Improves fuel economy. Promotes cleaner combustion & exhaust. Includes fast, no-spilling filling spout in every carton. Meets ISO 22241 requirements. API certified. Reduces harmful NOx emissions. Non-Flammable. Non-Hazardous. Size - 9.46 L