? [Smart Design] - Working together with an extension bit holder and a socket adapter, burnishing bits and extracting bits designed separately enables casual changes of the bits without flipping, timeless and effortless for work ?[ Industrial Grade] - Tacklife 18pcs damaged screw extractor set covers higher possibility of extraction for more broken screws or bolts of different sizes(2-12mm) and the self-centering drill tips can work on jagged, uneven rough breaks ? [Adequate Quality ]- S2 material (hot work die steel) with maximize rust and corrosion protection, hardness can reach to 62HRC for strength, flexibility and durability; Serrations on extractor(collect) result in greater torque for hard to remove bolts ? [Powerful Fittings Supply] - Extension bit holder(6.35mm,1/4'') and socket adapter (4mm, 5/32'' ) of the screw remover set suits all the brand household electric drills; Magnetism inside the holder and adapter keeps the bits from dropping, so do small bolts or screws ? [Easy for Use] - Separate drill bits and stripper bits simplified the entire process. You do not have to turn over the extractor or re-tension the drill chuck for extraction