Surgical and medical instruments and apparatus, namely, pointers, electro-medical apparatus, namely, calibration devices, tracker and reference markers, fluoroscopes and X-ray generators for the positioning of, for the determination of the position of and for the three-dimensional representation of implants and mounting elements, namely, internal fixations, virtual screws and screwdrivers and structural parts therefor

portable navigation aids, namely combined global positioning system ("GPS") and map display units