Designed for the sole purpose of extracting broken, stuck, stripped and damaged screws, this Extractor bit set will back them out quick & slick. Made from H.S.S. 4341 alloy with hardness rated at 63-65hrc, they will break through the rustiest and crustiest & sink deep into most metal fasteners using just a drill. The kit includes 6 bits, ranging from #0 up to #4. Each bit has two different heads, one drills a hole in the middle of the snapped-head fastener, the other is used to extract it.