Prestone(R) Command(R) Extended Service Interval (ESI) antifreeze+coolant (ready to use) is designed to work with all Class 6-8 vehicles. It is compatible with any iC (internal combustion) engine. This formula is Nitrited and precharged with supplemental coolant additive (SCA). Command ESI is a stabilized, low silicate formula, which helps reduce deposits and hard water scale buildup. There are no phosphates in this formula. Command ESI requires monitoring and maintaining the additive levels (SCAs).