Features Specifications: Material: HHS(drill bits), tool steel(extractors) Suitable Screws(for reference only): #1 for M3~M3.5 #2 for M4~M4.5 #3 for M5~M7 #4 for M8~M9 #5 for M10~M12 Drill Bits Diameter: 2.0mm, 3.0mm, 4.0mm, 6.5mm, 7.5mm Features: This set is designed to remove damaged, or stripped screws, bolts, fasteners. Drill bits are made of high speed steel for high hardness that could drill on most screws. Tool steel extractors have left handed spiral flute designed for extra gripping power. Easy to use, drill a hole in the center of broken screw first with proper drill bit, then use a proper extractor to take screw out. Come with an tap handle that can hold extractor firmly; for the large extractor, you may use an adjustable wrench. Package Includes: 1 x Broken Screw Extractor Set Package List