SK TurboSockets remove slotted and Phillips head screws too tight for a screwdriver. Even screws, nuts and bolts with very thin, rounded or tapered heads can be removed. Also removes a wide variety a wide variety of other problem fasteners like oil pan plugs, corroded marine nuts and bolts, and manifold nuts. Fast and easy to use Removes nuts, bolts and screws from 1/8 to 1/4, 3.5mm to 6mm and #4 to #10, and studs from 3/8 to 3/4 and 10mm to 19mm