Tiefenmesser / Depth gauge

Tiefenmesser / Depth gauge for all available steal rulers. It is 150mm high and fits out of the box the 150mm x 15 mm x 0.5 mm rulers. However, you can scale it according to your needs.
I would suggest you only scale in X and Y as this way you know the top is at 150mm (which is my reference point but you can obviously mark additional points.

After some trials I came up with this design that makes it easy to insert the ruler. Without the holes there was too much friction.

NOTE: Print on its head as shown in the picture of Cura.