350z HR HKS M-Series Super Fire Spark Plugs - for stock normally aspirated engines - Set of 6

The Outer Electrode features a shortened tip design and tapered shape while maintaining the necessary space for proper ignition. Short Type Outer Electrode (Anti-Vibration)The outer electrode has been shortened and engineered with the ideal shape to decrease weight for resistance against vibration. This anti-vibration design improves longevity of the outer electrode. Thermal EdgeAfter long idling or various combustion conditions carbon buildup can occur causing misfires. The Thermal Edge of the ceramic insulator will discharge to help decrease carbon deposits. Spark Support GapDischarges will occur in the Spark Support Gap (space between the tip of insulator and the base of the outer electrode) to help prevent carbon buildup.