credit card caliper

This caliper is designed to be carried in a wallet (85*54*2.3 mm).
It should have enough clearance to work. But it is not tested yet.

It is metric, has an original ruler without numbers, and created to be printed in a few layer in one area per layer, to avoid loosing precision in printing the scale. The lower scale is thought for a precision of 0.1mm, although it really depends on printer precision.

I did not go all the way to have a locking pin for measurement comparison. And the str