When added to gasoline: cleans and lubricates fuel injectors and carburetors. Improves gas mileage. Reduces and prevents varnish and gum build-up. Extends spark plug life. Safe for catalytic converters and oxygen sensors. When added to engine oil: prevents Valve sticking and clatter. Fortifies properties of engine oil, prevents breakdown caused by extreme temperatures. Promotes easier cold weather starts. Reduces and prevents sludge and acid formation. For all marine engines- inboard and outboard.