Mitutoyo 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-.78" / 20mm Measuring Range 0.0005" / 0.01mm Resolution 0.0015" / 0.03mm Accuracy 3.2" / 38mm Max Measuring Depth - Reach 0.97" Upper Contact Point Length 0.10" Lower Contact Point Length 0.059" / 1.5mm Diameter Ball Upper & Lower Contact Points