Hapco Lead Replacement Formula provides maximum lubrication to any fuel system. This formula is designed to help fuel become more efficient and increase fuel economy. It replaces lead while acting as an octane booster and valve lubricant. Does not contain solvents or lead. For Best Results: Use regularly as you fill up. One 16 oz. bottle will treat up to 25 gallons. Great to use in all gasoline, diesel and marine engines. Sensor safe and will not harm oxygen sensor or catalytic converter.