Gator Grip The Original Self-Adjusting Universal Socket with Power Drill Adapter. Self-Adjusts for Shape and Size as well as Standard and Metric application 3/8 Drive Professional Grade Socket. Fits  to  Standard and 7mm-19mm Metric. Self-Adjusts for all shapes and size fasteners, except a perfectly round head, just file an edge. Works especially well on rusted and damaged heads. Has a torque of over 100 LB/FT of power Works on a power drill.  power drill adapter included Replaced a toolbox full of tools. So easy to use, not only for the tradesman, but easy enough for anyone to use