ACCEL 0116-4 Performance Spark Plug, (Pack of 4) Copper Core Nickel/Chrome Steel Copper-Glass Gas-Tight Seal Electric Heat Seal Five-Rib Aluminum Insulator Less Flame Dissipation Delivers significantly more power at high rpm C cut ground electrode unshrouds the center electrode Creates a considerably hotter spark, reduces misfire, and minimizes flame dissipation Provides instant throttle response and noticeably better fuel economy Seven different models available, each specially designed for a specific heat range