One for (almost) all: the universal socket accepts all screw head sizes from 7 to 19 mm (1/4 to 3/4 inch). This allows the screw heads (external hex) 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 painstakingly tightened with pliers, can be unscrewed in one go. The perfect addition to your toolbox! | 303886 The essential aid for unscrewing damaged and deformed screw heads! Made of chrome vanadium steel (CRV) - rustproof, extremely strong and durable. 54 high quality spring steel pins automatically encompass all shapes (except a circular shape). Ideal for use with a screwdriver or cordless drill. Their drill chuck fits precisely into the supplied adapter (standard bit size 1/4"). Usage: Place the universal socket (3/8") 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 it and go!