This set is used to remove damaged, rusted or worn screws, studs, bolts and staples. High speed steel screw drill bit, double hardened, high hardness, suitable for drilling M3-M12 screws . Extractor made of high quality tool steel with left-handed spiral groove for increased gripping power. Easy to use, just use a suitable drill to drill a hole in the center of the broken screw first, then use a suitable extractor to remove the screw. A tap handle is included which can hold the extractor firmly, for the large extractor you can use an adjustable wrench. Supplied quantity: Eleven pieces Note: The data is manual measurement. Please allow an error of 1-156cm due to differences between light and display, there will be a certain color difference, the specific reception shall prevail.