Denso ZU Platinum spark plugs are designed to meet the needs of high power, high performance motorcycle engines. Denso ZU plugs are designed to improve ignition performance, aid fuel economy, Smooth the running of the engine and help reduce emissions thanks to a cleaner, more efficient burn in the combustion chamber.When a spark plug is used, most of the wear takes place on the centre electrode. This is due to the direction of the spark. The centre of the electrode is therefore made from a high quality copper cored nickel chrome alloy. Denso spark plugs all feature:Alumina Powder Insulator For Exceptional Insulation And Thermal ConductivityFive Rid Insulator Design Reduces Voltage Loss And Improves InsulationSpecial Copper Glass Seal Bonds Centre Electrode And Insulator For Gas Tight SealThin Platinum Electrode Generates A Stronger Spark.