What are the differences between F, N and FN in the coating thickness gauge? F stands for ferrous ferromagnetic substrate. The F-type coating thickness gauge adopts the principle of electromagnetic induction to measure non-ferromagnetic coatings and coatings on ferromagnetic metal substrates such as steel and iron, such as: paint, powder, plastic, rubber, synthetic materials, phosphating layer, chromium, zinc, lead, aluminum, tin, cadmium, porcelain, enamel, oxide layer, etc. N stands for Non-ferrous non-ferrous substrate, N-type coating thickness gauge adopts the principle of eddy current; to measure the enamel, rubber, paint, plastic layer, etc. on copper, aluminum, zinc, tin and other substrates with eddy current sensors. The FN type coating thickness gauge adopts both the principle of electromagnetic induction and the principle of eddy current. It is a two-in-one coating thickness gauge of F type and N type. Use see above. Magnetic thickness gauge with one F probe; FN refers to magnetic and eddy current 2-in-1 coating thickness gauge with two probes. Function: Measuring the thickness of non-magnetic coatings on magnetically conductive objects and non-conductive coatings on non-magnetic metal substrates Application: Use magnetic sensors to measure non-ferromagnetic coatings and coatings on ferromagnetic metal substrates such as steel and iron, such as paint, powder, plastic, rubber, synthetic materials, phosphating layers, chromium, zinc, lead, aluminum, tin, cadmium, porcelain, enamel, oxide layers, etc. Use eddy current sensors to measure enamel, rubber, paint, plastic layers, etc. on copper, aluminum, zinc, tin, etc. substrates. Widely used in manufacturing, metal processing, chemical industry, commodity inspection and other inspection fields.