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. Interchangeable Anvil is attached to a Micrometer Head for accurate dimensional setting. Wide measuring range with sub-anvils. Specifications include... 16" - 24" Measuring Range 0.0001" Graduations (2923AB-10 Dial Indicator) Accuracy: .00008" / 2um 2" Micrometer Head Travel Sub-Anvil: 2" & 4"