Quicksilver 843220Q NGK IZFR6J Laser Iridium Spark Plug, 1-Pack NGK Laser Iridium Spark Plugs deliver superior ignitability, longer service life with a copper core and ribbed suppressor seal for durability and performance 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 Don't just clean used spark plugs, replace them with new plugs for better performance Replace all the engine plugs at the same time