✨ 5/16-18 Helicoil Thread Repair Kit, Thread Repair Tool with HSS Drill Bit & Thread Inserts, SAE Thread Repair Installation Kit for Rethreading Internal Threads with Carry Case ✨. Engineered for versatility, the kit effectively repairs threads in materials such as aluminum, cast iron, carbon steel, brass, and magnesium alloy, making it suitable for spark plug ports, engine blocks, hydraulic systems, and machinery fittings.