A telescoping gauge and its set is a measuring tool with spring-loaded plunges used together with a micrometer to measure the inside of holes or bores. A telescoping gauge is an indirect measuring device, the head of which can be positioned inside holes or openings and then extended to touch the walls. The gauge can then be extracted, and the size of the extended head can be measured with a micrometer or vernier caliper to determine the interior radius of the hole.
