The ASTM MPI Test Block, which is used in magnetic particle inspection, will assist you in maintaining your magnetic particle process by validating magnetic particle performance. It contains coarse and fine surface and subsurface defects in both directions and can be used to check for magnetic particle deterioration, compare different magnetic powders, verify sensitivity or visibility, or ensure field direction and strength. Most industrial and military standards for artificial test specimens are met or exceeded, and MIL-STD-271 is followed.