.This precision kit allows the user to extract bolts which are corroded, or augmented and need to be removed without damaging the casing or thread from which the bolt was placed into. Manufactured from SNCM + V hardened steel for maximum durability. Simply drill a hole into the bolt, remove the drill, choose a suitable sized bolt extractor to insert into the hole and use a manual wrench to work the bolt extractor anticlockwise, thus removing the bolt. Specifications • Bolt extractor sizes: • 3/8" Drive • 2, 3, 4, 6, 8, 10mm • SNCM + V Hardened steel • Instructions included • Guide for drill sizes to be used with extractors