Digital eddy current test instruments for non-destructive testing of metal components, mass-produced parts, and semi-finished products using Preventive Multi-Filter Technology (PMFT). A comparative test for material properties such as hardness, material, tensile strength, heat treatment, or alloy. The new ibg family of digital structure test instruments distinguishes itself with the well-proven Multi-Frequency Technology and ibg’s good-part-only-concept, furthermore, the Simultaneous Harmonic Analysis iSHA and the optional temperature-adaptive structure test iTAS, both unique ibg innovations, offer enhanced opportunities for eddy current structure testing.