They make it much easier to extract broken bolts and studs without having to pre drill first, as you would have to do when using a regular screw extractor.
It also eliminates searching for the matching drill bit, as the bits are included and they all come in an organized and clearly labeled, metal index box. The bits are made of Cobalt and the screw extractors are machined, high speed steel.
• 5 multi-fluted, machined alloy steel screw extractors.
• Extractor sizes: #1, #2, #3, #4, & #5
• 5 Left-hand Cobalt drill bits.
• Drill bit sizes: 5/64”, 7/64”, 5/32”, 1/4”, and 19/64”
• Metal Index Box