They re the spark plugs high performance recreational vehicles respond to the best and serious riders depend on the most. NGK Iridium IX spark plugs ignite a whole new way of enjoying faster starting and quicker acceleration on demand, and drawing peak fuel efficiency and longer life from your engine under the most demanding riding environments. You ll never go back to conventional spark plugs. Why would you, when NGK Iridium IX spells the future of premium performance? The next time you look for spark plugs for your ATV or Snowmobile, think NGK Iridium IX Spark Plugs.