... F-typeMagnetic inductionMeasure the thickness of Non-magnetic coating layers on magnetic substrate.Such as: (enamel,rubber,paints,plastics, ... NF-typeEddy currentMeasure the thickness of non-conductive coating layers on non-magnetic substrate.Such as: enamel,rubber, paint, ... insulation not conduct electricity.All coating thickness gauges are FN type double function !Product Feature: (1)It meets the ...