Our flutes are designed to be embedded deep into the metal as you rotate the tool, so the resistance of the fastener increases the grip of the extractor Bearing steel material, practical and Bolt extraction kit helps to make studs, bolts, socket screws and fittings faster No matter wood or metal jobs, the bolt remover is ideal for construction, automotive, home projects, or industrial applications Flute screw extractor dimensions are engraved on the extractor for easy identification, Manufacturer: Rxgiasup