For removing Machine Screws and Broken Hand Taps;Tapered square shank fits into manual brace tools and drivers handles for added cutting pressure;Threads per inch need not be specified as Tap Extractors will fit both NC and NF taps;Hardened steel fingers of Walton Tap Extractors fit in the flutes of a broken tap to back it out simply and safely;When fingers become bent or broken or are too short for further use, replacement fingers are available