Mitutoyo Tube Thickness Caliper-Type Gage Mitutoyo's versatile OD measuring gage for hole diameters, groove thickness, tube thickness, and hard to reach dimensions. Features include... 0-1.97" / 50mm Measuring Range 0.001" / 0.02mm Resolution 0.003" / 0.08mm Accuracy 6.57" / 167mm Max Measuring Depth 1.97" / 50mm Upper Contact Disc Diameter 1.97" / 50mm Lower Contact Disc Diameter SPC Output