Applications: 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, aluminium tile, some alloy tile, paper etc. The N probes measure the thickness of non-magnetic coatings on non-magnetic metals. It is used on anodizing, varnish, paint, enamel, plastic coatings, powder, etc. applied to aluminum, brass, non-magnetic stainless steel, etc. Specifications: Principle: Magnetic Induction / Eddy Current (F / NF) Measuring Range: 0~1250 um / 0~50 mil Resolution: 0.1 um / 1 um Accuracy: +/- 1~3%n or +/- 2.5 um Min. Radius Workpiece: F Type: convex 1.5 mm / concave 25 mm NF Type: convex 3 mm / concave 50 mm Min. Measuring Area: 6 mm Min. Sample Thickness: 0.3 mm Auto Power Off Metric / Imperial: Convertible Battery Indicator: Low Battery Indicator Operating Conditions: Temp. 0~50C; Humidity: ?80%RH Power Supply: 4 x 1.5 V AAA (UM-4) Battery Dimensions: 126 x 65 x 27 mm Weight: 81g (Not Including Batteries) Package includes:Main Unit Calibration Base Set (F Type / NF Type) CTG-BS Calibration Foils CTG-CF (1 set, 4 pieces) Carrying Case Operation Manual Optional accessories: USB, RS-232C data cable with