The Mileage Buster - Set of 2 #1 Formulation in the world to increase gas mileage! Great for Gas and Diesel - including ethanol gasoline and bio-diesel fuel. Gain up to 20% more miles per gallon - One bottle could give you the equivalent of 30 gallons of gas in EXTRA mileage! Restores and improves engine performance. Reduces emissions by burning fuel more completely - which improves fuel mileage.