NGK TR7IX Spark Plug, Iridium IX, Each

These NGK Iridium IX spark plugs feature an ultra-fine center electrode that's designed just thick enough to ensure the maximum durability and life of the spark plugs, and just thin enough to create an accurate and consistent spark. They represent the ultimate evolution of spark plug technology and performance. Iridium is significantly stronger than any metal used in spark plugs today. It's the hardest metal used (in fact, iridium is 6 times harder than platinum), which has allowed NGK engineers to reduce the voltage requirement for a spark.