Digital 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-.8" / 20mm Measuring Range 0.0005" / 0.010mm Resolution +0.001" / 0.02mm Accuracy 3.15" / 80mm Max Measuring Depth - Reach 0.97" Upper Contact Point Length 0.97" Lower Contact Point Length 0.24" / 6mm Diameter Disc Upper & Lower Contact Points