Fowler-Bowers XTD3 Digital Internal Micrometer These bore gages have been designed to further simplify the accurate measurement of bores. All XT instruments offer fixed anvils. Sizes above 1"/25mm offer extended travel. They are available as individual instruments or in complete sets. Includes Bluetooth Connectivity Package includes the following... Measuring Head Display Handle Setting Ring Specifications include... .500"-.625" (12.5-16mm) Measuring Range 0.00005" / 0.001mm Resolution 2.44" (62mm) Measuring Depth Large easy-to-read display. Features include... Self Centering 3 point head USB & Bluetooth Connectivity IP67 Rated Protection Ratchet Stop