Prestone® Command® Nitrite Free (NF-OAT) Extended Life (ELC) antifreeze+coolant (Concentrate) is designed to work with all Class 1-8 vehicles; Heavy Duty and Light Duty. It is compatible with all vehicles, coolant colors (LD) and any Nitrite Free OAT engine (HD). When compared to ESI & low silicate conventional, it is designed to help lower maintenance costs and improve water pump life. This formula is Nitrite Free and provides excellent protection for aluminum and all other engine metals. Command NF-OAT ELC protects against liner pitting and corrosion protections.