E3 Spark Plug E3.66 Automotive Spark Plug, Pack of 1 Near elimination of performance inhibiting carbon deposits, dramatically longer plug life and a 5-year/100,000 mile limited warranty DiamondFire electrode technology that creates a superior spark and resulting flame front extending further into the cylinder, producing more localized pressure Significant potential power increase: &gt; 6% to 12% (depending on engine class) Significant potential fuel efficiency improvement: &gt; 4% to 13% (depending on engine class) Drastic potential emissions reduction when used in 2 and 4-stroke engines (after 50 hours): 58% CO emissions reduction, 42% hydrocarbon reduction