... as F-typeMagnetic inductionMeasure the thickness of Non-magnetic coating layers on magnetic substrate.Such as: (enamel,rubber,paints, ... along as it is non-magnetic NF-typeEddy currentMeasure the thickness of non-conductive coating layers on non-magnetic substrate.Such as: enamel ... materials,anodic-oxide layer on copper,aluminum,zinc,tin,non-magnetic stainless steel,gold and silver. Cover layer only ...