... side:V-shaped groove, Built-in probe CM8801F: Fe-type: application to permeability substrate (such as iron, steel, etc.) coating ... measurement, LCD clock display "Fe"CM8801N: NFe type: Suitable for inter permeability substrate than the substrate (such ... .) coating measurement, LCD always display "NFe"CM8801FN: Complex type: Suitable for all metal matrix coating measurement, depending on ...