Information is oriented when presented to a user on a display surface, so that the information can be readily read andor used by the user. Specifically, this invention allows the use of a straight blade, a three-blade or a five-blade driver with the same fastener head. Each of the radial parts comprises a recess arranged such that during assembly of said segments pairs of neighboring recesses form a hole which again engages in a corresponding peg on the hub in a form fitting manner. A lever arm has a near end and a distal end. The predetermined area is changed in accordance with a condition of whether or not an object is near the eyepiece portion. The workpiece is moved through an inductor to inductively heat treat the workpiece with electric power of varying frequency and duty cycle or amplitude control to control the magnitude of electric power as the frequency changes.