Material: The stripped screw extractor is made of 4241 high speed steel. High hardness, durable and easily removes damaged screws. Size: The screw extractor includes 10 pieces drill bits (sizes from #1-#10), 10 pieces extractor (sizes from #1-#10) 1 piece of extension bit holder and 1 piece of socket adapter. It offers a model specification to help you remove different sizes (1-12mm) of damaged screws or bolts. Extension: The magnetic bit holder with an adjustable collar can help absorb the high torque of new impact drivers. Quick Change Bit Holder solves the drill bit that the drill bit was not long enough to reach what you were trying to drill. Widely Use: High precision hole position, ideal damaged bolts and screw remover tools, suitable for most common drill bits and different sizes of screws or bolts, such as Allen bolts, machine screws, lag bolts, wood screws, hex bolts, sheet metal screws. Note: You'd better install them on the electric drill (suitable for a basic electric hand drill) instead of the hammer drill when removing damaged screws. In addition, must be reverse use in the whole process and in low speed and reverse use, or you will be injured. Note: It does not include other things, the color is based on the first picture, and the other pictures only show the effect. Due to the differences between different monitors, the picture may not reflect the actual color of the item. . due to manual measurement. Please allow the deviation. Thank you! becomeveryrich