Features Reverse spiral design for maximum grip, so helps relieving your labor Made of high quality Chrome vanadium steel material,and treated by heat treatment,with high hardness and wear resistance This screw extractor set is designed to remove broken studs and bolts Recommended drill bit size (for location hole) etched on each extractor,suitable for high applications This product contains 10 pcs different size extractors of 3.2-10.3mm, so can meet your repair work under different circumstances Specifications: Material: chromium vanadium steel Color: gray Quantity: 10 pcs Weight: 537g 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) Package Included: 10 x Screw Extractor  1 x Red Case Features : This screw extractor set is designed to remove broken studs and bolts. Made of high quality Chrome vanadium steel material,and treated by heat treatment,with high hardness and wear resistance. Reverse spiral design for maximum grip, so helps relieving your labor. Recommended drill bit size (for location hole) etched on each extractor,suitable for high torque applications. This product contains 10 pcs different size extractors of 3.2-10.3mm, so can meet your repair work under different circumstances. Descriptions: This screw extractor set is designed to remove broken studs and bolts. Made of high quality Chrome vanadium steel material, and treated by heat treatment, with high hardness and wear resistance. And contains 10 pcs different size extractors of 3.2-10.3mm, so can meet your repair work under different circumstances.. Package List