【Remove Broken Nails and Bolts】This screw extractor set is designed to remove broken nails and bolts. High Hardness and Wear Resistance: Made of high quality chrome vanadium steel, and processed by heat treatment, with high hardness and wear resistance. Reverse Spiral Design: Reverse spiral design for maximum grip, helps relieve your work. High Torque Applications: Recommended drill bit size (for location hole) engraved on each extractor, suitable for high torque applications. 3.2-10.3mm Different Size Extractors: This product contains 10 different size extractors from 3.2-10.3mm, to meet your repair work in different circumstances.