For unscrewing ruined screws and threaded bolts without damaging threads. Made from chrome vanadium steel, hardened, surface burnished. RN2610003 contains screw extractor sizes 1 to 5 (1/8'' to 3/4''). RN2620003 contains screw extractor sizes 1 to 6 (1/8'' to 1''). RN2630003 contains screw extractor sizes 1 to 8 (1/8'' to 2'').