Slider cải tiến cho thước cặp vernier (spring loaded)

The main part is missing? No, it is not ;-)

I did not want to steal the clicks from the original designer on this very nice design. Therefore I published only the slider here, which I did myself. Please get the the ruler from the original design: https://www.printables.com/model/1119026-updated-calipers-cm

Printing

You will need supports on the backside of the lower extension. But this plane is not relevant for the measurement accuracy, and is typically not visible, so don't worry about a somewhat rough surface as a result of the supports touching there. 

Material

To achieve the needed springingness of the two printed springs, I recommend to use PETG.

Happy printing!