Red Line SI-1 Complete Fuel System Cleaner contains the most powerful high-temperature detergents and synthetic lubricants designed to clean gasoline fuel injectors. SI-1 also cleans carburetors, intake valves, and combustion chambers. One concentrated treatment of a 15 ounce bottle to 15 gallons of gas can restore injector flow to nearly 100% -- even after years of neglect. One bottle to a tank of gas can reduce octane requirements by two numbers. Removes and prevents rust, gum and varnish; lubricates upper cylinder area, and cleans emission control systems. Will not harm catalytic converters and sensors. Safe for continual use. One bottle treats 15 to 100 gallons.