Digital Electronic Internal Caliper Gage These internal caliper gages are designed for measuring Internal Diameters that might be difficult to get to. They are also often galled a Groove Gage because of their perfect design for measuring IDs on internal grooves. Features include... 0.59-2.55" / 15-65mm Measuring Range 0.001" / 0.02mm Resolution +0.002" / 0.050mm Accuracy 7.4" / 188mm Max Measuring Depth Ball 0.059" / 1.5mm Radius LCD Analog / Digital Display IP67 Rated Protection Function Include... Zeroset Preset Auto Power Off In / Metric Conversion Data Hold Min / Max Value Hold