Very strong tool made from high quality steel. I don't know what steel is used, but the tip is hard enough not to deform, the shaft is flexible enough not to break, and that thin little part where the hex ball meets the shaft is surprisingly strong . I've used this screwdriver quite a bit, and sometimes when removing a stuck screw I've tightened it just a little more than comfortably, but with no damage. But let me be clear that the grip is quite large for a shank of this size, so be aware that