SCIENTIFIC MEASURING AND NON DESTRUCTIVE TESTING APPARATUSES AND INSTRUMENTS, NAMELY, EDDY CURRENT TESTING INSTRUMENTS AND SCANNERS; ELECTRONICAL MEASURING, TESTING AND INSPECTION, NAMELY, EDDY CURRENT TESTING INSTRUMENTS AND SCANNERS; DEVICES FOR NON-DESTRUCTIVE (DESTRUCTION-FREE) EXAMINATION OF METAL-BASED MATERIAL (FERROMAGNETIC AND NON-FERROMAGNETIC-MATERIAL) CONSTRUCTIONS FOR DETECTION AND DETERMINATION OF DAMAGES, NAMELY, EDDY CURRENT TESTING INSTRUMENTS AND SCANNERS