Powerbuilt 648511 6 Pc Screw Extractor Set For removing broken studs, screws, bolts, etc. Left-hand spiral blade design grips screw when turned into hole drilled to specified size Kit contains extractors Removes broken studs, screws, bolts, etc Left-hand spiral blade design grips screw when turned into hole drilled to specified size Extractors included: 3/16-1/4 inch, 1/4 inch-5/16 inch, 5/16 inch-7/16 inch, 7/16 inch-9/16 inch, 9/16 inch-3/4 inch, 3/4 inch-1 inch Plastic tray keeps everything organized