Dura Lube Severe Fuel System Cleaner: * Precisely formulated to clean the entire fuel delivery system * Helps to remove valve stem gum * Compatible with all grades of gasoline fuel including E-10, E-15 and E-85 Ethanol blends * Not for use in diesel engines * Will not harm catalytic converters * 16 fl oz bottle treats up to 42 gallons of fuel * For best results, use every 3000 miles