ELECTRONIC INSTRUMENTS FOR NON-DESTRUCTIVE MATERIAL TESTING; ELECTRONIC INSTRUMENTS FOR MEASURING ELECTRICAL AND MAGNETIC PROPERTIES, AND ELECTRONIC INSTRUMENTS FOR MEASURING COATING AND FOIL THICKNESS OF TANGIBLE OBJECTS; DETECTORS FOR FERROMAGNETIC AND METALLIC OBJECTS; ELECTRONIC DATA PROCESSORS FOR THE CONTROL OF AFOREMENTIONED GOODS AND FOR EVALUATING THE INFORMATION OBTAINED THEREIN; PARTS FOR ALL OF THE ABOVE AFOREMENTIONED GOODS; COMPUTER PROGRAMS STORED ON DATA CARRIERS FOR THE CONTR...