Champion RN4C Marine Spark PlugChampion marine spark plugs are quality OEM replacements. The Champion RN4C Spark Plug features a copper core electrode that provides increased conductivity and heat control for good overall wear. These marine spark plugs are designed to resist overheating under heavy engine loads.Resists foulingSuperior corrosion resistanceDependable and proven performanceIncreased conductivity and heat control for good overall wearChampion Spark Plug # 104