... Test side:V-shaped groove, Built-in probe CM8801F: Fe-type: application to permeability substrate (such as iron, steel, ... etc.) coating measurement, LCD always display "NFe"CM8801FN: Complex type: Suitable for all metal matrix coating measurement, depending on the ... substrate may be, LCD will display "NFe" or "Fe", type of instrument can automatically recognize substrateCoating thickness: 0 ~ 1000um ± ...