HKS M45XL Spark Plugs Optima, Stinger, & K5

HKS M-Series Super Fire Racing spark plugs are high performance Iridium plugs designed to handle advanced levels of tuning and provide Improved ignition performance, durability and anti-carbon build-up Features & Specs:  0.6mm Iridium Alloy Center Electrode: Iridium Alloy Center Electrode reduces voltage requirement as well as improving ignition performance and durability   Outer Electrode with Platinum Chip: The Outer Electrode incorporates a square platinum chip which improves durability, and when combined with the iridium center electrode boosts ignition performance   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 the longevity of the outer electrode   Thermal Edge: After long idling or various combustion conditions carbon buildup can occur causing misfires. The Thermal Edge of the ceramic insulator will discharge