NGK Fine Wire Tipped Center Electrode Laser Iridium Spark Plugs deliver slow wear rate, stable idle, superior anti-fouling, improved fuel efficiency and lower emissions Check your engine owner’s manual for the correct spark plug and use only the plug as recommended by your engine’s original equipment manufacturer NGK Trivalent metal plating also provides superior anti-corrosion in the marine environment and anti-seizing for easier removal Replace all the engine plugs at the same time