Mahr MarCator 810 A dial <a href="https://en.wikipedia.org/wiki/Indicator_(distance_amplifying_instrument)" class="extiw" title="en:Indicator (distance amplifying instrument)">indicator</a>, 10 mm range, 0.01 mm scale.
<a href="//commons.wikimedia.org/wiki/User:Lucasbosch" title="User:Lucasbosch">Lucasbosch</a>
CC BY-SA 3.0
<span class="int-own-work" lang="en">Own work</span>