Irwin Phillips #1 X 1-15/16 in. L Power Bit S2 Tool Steel 1 pc

A screwdriver bit is a tool for driving screws and one that can be fitted to most drilling power tools. All screws have a head with a contour such that an appropriate screwdriver tip can be engaged in it in such a way that the application of sufficient torque to the screwdriver will cause the screw to rotate.