Mitutoyo 155-903 Imperial Telescoping Gauge Set .313-6" (Set of 6)

A set of six transfer gauges that enables the diameter of holes, bores or grooves to be measured with outside micrometers or calipers.
Set consists of 6 telescoping gauges; .313-5", .50-.75", .75-1.25", 1.250-2.125", 2.125-3.500", 3.5-6.0".
Enables small hole, bore and groove measurement using existing workshop tools.
Knurled finish provides secure handling and easy locking.
In operation the spring loaded plunger of a gauge is allowed to expand within the feature to be measured and then locked in place using the knurled rotary control on the end of the handle.
In practice some manipulation is necessary to ensure that the minimum size has been captured, after which the gauge is carefully withdrawn so that the dimension across the contact surfaces can be measured.