One for (almost) all: The universal socket takes all screw head sizes from 7-19 mm (1/4 to 3/4 inch). This allows screw heads (external hexagon) to be easily screwed into the material and loosened. And that's not all. Even hook, eye and ring screws, which otherwise have to be laboriously gripped with pliers, can be unscrewed in one go. The perfect addition to your tool box! | 303886 THE indispensable help to unscrew damaged and deformed screw heads! Made of chrome vanadium steel (CRV) - rustproof, extremely resistant and durable. 54 high-quality, spring-loaded steel pins automatically encompass every shape (except for a circular one). Ideal for use with a cordless screwdriver or drill. Their drill chuck fits the supplied adapter (1/4 inch standard bit size) precisely. Use: Put the universal socket (3/8 inch) on a ratchet/ratchet or with the adapter in the drill chuck of the cordless screwdriver. Then place it in the middle of the screw, press down and off you go!