This set is designed to remove damaged, rusted or worn screws, bolts and fasteners. The drill bits are made of high speed steel for high hardness and can drill through most screws. Tool steel extractors feature a left-handed spiral groove designed for extra gripping power. Easy to use: First, drill a hole in the center of the broken screw with a suitable drill bit, then use a suitable extractor to remove it. Come with a tap that can hold the extractor tightly; for the large puller, you can use an adjustable wrench