TOP TIERTM Diesel Fuel certification is awarded to diesel fuels suppliers that have tested and approve their formulations by a consortium of automotive OEMs, and it comes with the assurance that the fuel will meet a higher standard of performance which includes: Reduction of internal and external fuel injector deposits, improved lubricity for less wear on critical fuel system components, improved fuel stability resulting in less deposits in the fuel system components, and, increased protection against water and particulates introduced into the fuel before being dispensed into the vehicle or equipment.