NGK V-Power Spark Plugs feature a “V” cut in the center electrode that helps direct ignition spark to the edge of the electrode to aid spark development increase ignitability and reduce quenching 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 This spark plug meets Mercury Marine original equipment manufacturer specifications to best protect your engine and ensure its optimum performance Don’t just clean used spark plugs, replace them with new plugs for better performance Don’t just clean used spark plugs, replace them with new plugs for better performance