Made of high-quality chrome vanadium steel and processed by heat treatment, with high hardness and wear resistance This screw extractor set is designed to remove broken studs and bolts Reverse spiral design for maximum grip, helping to relieve your work Recommended drill bit size (for the locating hole) is engraved on each extractor, suitable for high-torque applications This product contains 10 extractors in different sizes from 3.2 to 10.3 mm, which can meet your repair work in different circumstances Descriptions: This screw extractor set is designed to remove broken studs and bolts. Made of high-quality chrome vanadium steel and processed by heat treatment, with high hardness and wear resistance. And contains 10 different size extractors from 3.2 to 10.3 mm, so that it can meet your repair work in different circumstances. Specifications: Material: Chrome Vanadium Steel Color: Gray Quantity: 10 pcs Size: 1/8"(3.2 mm), 5/32"(4 mm), 3/16"(4.8 mm), 7/32"(5.5 mm), 1/4"(6.3 mm), 9/32"(7