Magnetic particle inspection (MPI) is a non-destructive testing method used to detect surface and near-surface discontinuities in ferromagnetic materials. The discussion highlights the various classes of inspection criteria, ranging from AA to G, which dictate the standards and procedures for conducting MPI tests. Key reference documents for further research include MIL-STD-1949, ASTM E 1444, and several AMS standards related to magnetic particle materials and methods. These documents provide essential guidelines for the application of both dry and wet methods in MPI. The conversation indicates a need for clarity on the specific number of tests conducted during this inspection process, suggesting that further exploration of the provided resources may be necessary for comprehensive understanding.