Prestone® Command® Cor-Guard® Nitrite Free (NF-OAT) Extended Life (ELC) antifreeze+coolant (ready to use) is designed to work with all Class 1-8 vehicles; Heavy Duty and Light Duty. COR-GUARD® technology increases uptime; More miles between service = Less cost to maintain. Utilizing Cor-Guard technology, this formula is designed to protect cooling system parts from corrosion and damage. It instantly protects against the spread of rust, corrosion, pitting, gunk, grime and build-up. It is one fluid that can be used for the whole fleet; all vehicles, coolant colors (LD) and any Nitrite Free OAT engine (HD). Service life is 1,000,000 Miles / 20,000 hrs [class 7-8 with wet sleeve liners]. 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, provides excellent protection for aluminum and all other engine metals and eliminates the need to add supplemental coolant additives.