Metric thread repair tools for spark plugs M5 M6 M8 M10 M121、Premium Materials: This metric thread repair kit includes drill bits and screw taps, heat treated to a resilience of HRC 50‑60, solid designed for enhanced durability and longevity. 2、Efficient Design: The 135° drill bits require minimal pressure, making the drilling process easier. Rubber coated installation and tang breakoff tools provide a comfortable and secure grip for efficient and safe usage. 3、Comprehensive Kit: Designed for convenience, this kit includes a variety of sizes (M5, M6, M8, M10, M12) to perfectly accommodate a wide range of automotive and engine repair tasks, particularly for spark plug cylinder insertion. 4、Practical Tool Set: Replace damaged threads with stronger material, this kit not only offers a fix but also an upgrade to the strength and lifespan of threaded connections, enhancing engine's performance. 5、Portable: The provided carry case keeps all your rethreading tools neatly organized for easy transport from one job to the next, ensuring a hassle free experience.