Thread size: 12×26.5mm Heat range: NGK #10 HKS is the first to release the high heat range tuning spark plug M12 long reach HEX size 14 for 86, BRZ and GT-R to the market.

• R35 GT-R stock's heat range is the same as NGK 8, NGK 9 to 86/BRZ, and the new HKS M50HL is the same as NGK 10. It's for a high tuning vehicles.
• Reinforced by making the outer electrode bigger(see the pictures below). Also could have a steady ignition and ignition speed at a high load and high RPM by putting the center electrode in the middle of the spark plug.
• Improved the anti-taint property by making thermal edge to prevent the carbon buildup which occurs for the tuned engines.

* Ensured wide area of combustion by optimizing the position of the outer electrode and central electrode. It has a more efficient flame spread than the normal iridium spark plug.