Made of high quality chrome vanadium steel and treated by heat treatment, with high hardness and wear resistance This screw extractor set is designed to remove broken studs and bolts Inverted spiral design for maximum grip, helping to ease your labor Recommended drill size (for locating hole) stamped on each puller, suitable for high torque applications This product contains 10 pieces of pullers with different sizes from 3.2mm to 10.3mm, 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 extractors of different sizes from 3.2mm to 10.3mm, so that they can meet your repair work under different circumstances. Specifications: Material: chrome vanadium steel Color: gray Quantity: 10 pcs Size: 1/8(3.2mm), 5/32(4mm), 3/16(4.8mm), 7/32(5.5mm) , 1/4(6.3mm), 9/32(7mm), 5/16(8mm), 11/32(8.7mm), 3/8(9.5mm), 13/32 (10.3mm) Features: 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. spiral design reversed for maximum grip, helping to ease your labor. Recommended drill size (for locating hole) stamped on each puller, suitable for high torque applications. This product contains 10 different size pullers from 3.2mm to 10.3mm, which can meet your repair work in different circumstances. Package included: 10 x screw extractor 1 x red case