Our flute is designed to embed themselves deeper into the metal as you turn the tool, so as the fastener resistance increases, the-extractor ' s grip increases Bolt remover that remove screws, whether working on wood or metal, are for ideal for construction, automotive, home projects or for industrial use bearing steel materials, practical and bolt extractor kit can helps faster studs, bolts, socket screws, and fittings flute screw extractor dimensions are engraved on the-extractor for easy identification, Manufacturer: LXJLXD