Application:The F probes measure the thickness of non-magnetic materials (e.g. paint, plastic, porcelain enamel, copper, zinc, aluminium, chrome etc.) on magnetic materials (e.g. iron, nickle etc.). often used to measure the thickness of galvanizing layer, lacquer layer, porcelain enamel layer, phosphide layer, copper tile, aluminum tile, some alloy tile, paper etc. The NF probe measure the thickness of non-metal coatings on non-magnetic metals. It is used on anodizing, varnish, paint, enamel, plastic coatings, powder, paper etc. applied to aluminum, brass, non-magnetic stainless steel, etc.