Mitutoyo's Dial Bore Gage offers interchangeable anvils and necessary accessories to perform close tolerance I.D. measurements. Carbide ball contact point for durability. Optional extension rods can be attached. A Digimatic Indicator can be attached in place of the dial gage. Specifications include... 2.0" - 6.0" Measuring Range 0.0001" Graduations (2923SB-10 Dial Indicator) Accuracy: .00008" / 2um 4 Spacers 11 Anvils