Back Cover with Flap for Dial Gauge 208.015

To be able to mount the [dial gauge 208.015](https://www.gimex-exactools.de/Shop/de/Klein-Messuhr--3-x-0-01-mm--17--m.html) on the [ CNC Alignment Collar from DIY3DTech](https://www.thingiverse.com/thing:2469960) it need a flap on its back side.
The attached back cover has such a flap. So the dial gauge can be used with this collar.
I used it to check the quality of the bed leveling of my device. https://youtu.be/mLAwB4jLXgA