Bosch (W8EC) Spark Plug Heavy Duty Yttrium-Enhanced Center Electrode with Copper Core Provides Superior Reliability and Durability Tapered Cut Nickel Chromium Ground Electrode Assists in Cold Weather Starts and Provides Increased Ignitability Nickel-Plated Rolled Threads Provide Anti-Seize and Corrosion Protection Metal Glass Fused Resistor Gives Maximum Interference Suppression Angular, 5-Rib Insulator Design Prevents Flashover