This kit includes 12 tools designed for broken key extraction.
Key extractors come typically in two forms: harpoons and hooks.
Both styles of extractors have benefits and are able to accomplish the task. In general, if the lock has a wide keyway the style doesn’t matter so much as the fact that it is thin and sharp.
To utilize the extractor you place it in the keyway and press all the pins up as high as possible and hook the broken key part with the extractor and pull it out.