Autolite XP3923-4PK Iridium XP Spark Plug, Pack of 4 Iridium-enhanced platinum alloy 0.6mm fine wire center electrode for improved ignitibility performance Patented V-trimmed platinum side wire technology resists wear OE equivalent design is engineered for every engine to ensure the right plug for your vehicle Designed for better overall durability with virtually no gap erosion for longer plug life Attached motor seat gasket and terminal nut