The Fowler-Bowers FB-3P-3-4-0.00025 Bore Gauge Micrometer Set is an internal bore gauge designed to measure bores from 3" to 4" with a 0.00025" resolution using a micrometer-style readout. This 3-point internal bore gauge combines precise inside-diameter measurement with a micrometer scale, making it suitable for inspecting cylindrical holes in precision-machined parts. The part number FB-3P-3-4-0.00025 identifies this specific gauge/micrometer combination for reliable, repeatable bore measurements across its 3–4 inch range.
