Used expressly for removing broken or seized screws. They are left-handed, for use on right-handed threads. The screw is first drilled out to the proper diameter for that extractor using the drills provided. The extractor is then inserted into this hole and turned counter-clockwise using the tap wrench. As the extractor is turned the flutes on the tool dig into the screw, causing it to lock tightly and apply sufficient torque to remove the screw.