The Nix Qnix Fe1.2mm magnetic thickness probe has a thickness measurement range of 0 to 1250 microns. Measurement accuracy is +/- (1 µm + 2% reading) < 2.0mm; when +/- 3% reading > 2.0mm, it is an optional probe for the Qnix5500 and Qnix9500 series Thickness Gauges.