Made of chrome vanadium steel, high hardness, anti-rust, strong and durable The drill diameters and recommended extraction diameters of broken screws are engraved on the housing The extractors and drill bits with great gripping force Ideal for removing damaged, rusted or stripped screws, studs, bolts, fastener, metal water tap and water tube, etc. The drill bits can also be used to drill holes on wood, metal, plastic, brick and wall, etc. Note: The data are all measured manually, please allow 1-3cm error due to differences in light and display, there may be some color differences, please refer to the actual item received.