Height gauge

Without anything to add scale this could possibly be some piece of gym equipment, or a torture device (or indeed both), but it's actually for setting the height of samples to go in an electron microscope.  I was wondering where it had got to, it had been sent to me by post but because it didn't fit in the pigeon holes it had just been left in the post room in a random place without anyone thinking to tell me, and I only thought to look at it because I was being nosey.