Extract 4-screw extractor kit for all drill bits and screws or bolts of any size, ideal for removal. Made of HSS 5% M35, it is durable , solid and not easily broken. Borehole and puller, convenient double-head design can increase efficiency.There is no need to drill deep holes with fine lines. Suitable for loose, broken, stuck or damaged screws It benefits all homeowners, carpenters, mechanics, artists, hobbyists etc. The 4 different sizes in diameters from 3mm to 12mm are available for your different needs. Double Head Puller Instructions: 1. Need an electric hand drill. 2. Remove the drill first and make a hole in the damaged screw, the speed should not be too fast. The deeper the hole, the higher the success rate (counterclockwise rotation). 3: Use a drill to drill a deep hole in the head of the screw, then turn the screwdriver counterclockwise until the screw is damaged until it is released. > Note: Please keep it in a dry place to avoid rust. Helical puller size: Diameter