Feature 1This set is designed to remove damaged, rusted or stripped screws, bolts, fasteners 2HSS extractors have left handed spiral flute designed for extra gripping power 3There are total 4 extractors in various sizes for screws of diameter from 3mm to 12mm 4Easy to use, drill a hole in the center of broken screw with one end first, then take screw out with the other end 5These extractors work with a cordless drill to remove wood screws or iron screwsSpecification Features: This set is designed to remove damaged, rusted or stripped screws, bolts, fasteners. HSS extractors have left handed spiral flute designed for extra gripping power. There are total 4 extractors in various sizes for screws of diameter from 3mm to 12mm. Easy to use, drill a hole in the center of broken screw with one end first, then take screw out with the other end. These extractors work with a cordless drill to remove wood screws or iron screws. Specifications: Material: HSS4341 Surface Finishing: Titanium plating Suitable Screws: 3mm~12mmwood screws or iron screws Package Includes: 4 x Extractors