Restores Damaged Threads with Precision: Specifically designed for repairing worn or damaged threads on bolts and studs, this set helps restore original thread shape without cutting new threads. Non-Cutting Design Preserves Thread Integrity: Unlike traditional cutting dies, these rethreading dies realign existing threads without crosscutting or undercutting—perfect for maintenance and repair tasks. Not for Hardened Threads or New Cuts: Engineered solely for thread restoration, not for cutting new threads or use on hardened materials, ensuring optimal tool performance and longer life. Durable High Carbon Alloy Steel Construction: Built from premium high carbon alloy steel to withstand repeated use and provide consistent results over the long haul. Includes Five Common Metric Sizes: Set contains hex rethreading dies in sizes 6.0 x 1.00, 7.0 x 1.00, 8.0 x 1.25, 10.0 x 1.50, and 12.0 x 1.75 to cover a wide range of metric fasteners.