501 Premium Diesel Fuel Improver Qt. Increases cetane number of any diesel fuel for quicker, smoother, quieter, more complete combustion Up to 42% cleaner exhaust emissions when measured by the opacity method Keeps injectors clean...even cleans up dirty injectors Reduces injector & injector pump wear caused by today's abrasive low sulfur fuels by as much as 26% Improves cold weather performance...lowers cold start temperatures & reduces warm-up time