Denso (3421) SK20HR11 Iridium Long Life Spark Plug, Pack of 1
Iridium plugs have an extremely long life as Iridium is 6x harder and 8x stronger than platinum. Because of the strength and hardness of iridium, there is virtually no electrode wear. This combined with a platinum tipped ground electrode, creates a spark plug that is almost impervious to wear even under extreme driving or racing conditions.