Fowler 54367024BT XTD3 2-2.625"/50-65mm measuring range Bluetooth electronic holemike has 3-point heads, 0.00005"/0.001mm graduation, 0.00020"/0.005mm accuracy, 3.15"/80mm depth and comes with full 5 year warranty. Features tungsten carbide measuring face and blind bore capability. This digital inside micrometer has a ratchet stop for consistent measuring and non-removable anvils. This holemike has 4 preset memories, larger easy-to-read display, direct inch/metric conversion, proximity and Bluetooth connectivity. It comes with a head, handle, setting ring and UKAS certificate for micrometer, head and setting ring, special anvils available upon request. Offers extended travel. The Fowler/Bowers XT3 Digital Internal Micrometers have been designed to further simplify the accurate measurement of bores. All XT instruments offer fixed anvils. Bore gauges measure holes, or bores, in a workpiece. Internal micrometers can only measure to the depth of their teeth while bore gauges allow more depth range. Bore gauges are typically calibrated with a setting ring and come in two types: simple and direct-measuring. Two-point contacts bore gages are better at measuring ovality, while three-point contacts are used to measure lobbing or triangular form error. Pistol-grip bore gauges are used for fast, single-handed operation with repeatable results from one operator to another. Bore gauges can also be used in special applications, such as measuring threads, spline pitch diameters, and deep bores. This product has full 5 year warranty offered by Fowler Precision. If you experience any problem contact Fowler directly for warranty claims. Fowler, an American company, manufactures inspection and measurement instruments such as electronic indicators, calipers, bore gages, and digital scales. The company, founded in 1946, is headquartered in Newton, MA.