I, well, I didn't really need these, masking tape and center marker works just fine, but I wanted these. So after browsing a bit I gave up and opened the Fusion 360 and just made a model myself. 

This may not be exatly perfectly as what you can buy, I just made it fast by feeling, not really measuring and thinking through all the different measurements this should have, but hey, resize for your own needs. 

I printed this with PETG to get it more flexible, after all, it's suppoused to be a clip but that makes all the corners a bit rounded and harder to stay where they're suppoused to stay, but since they work, I didn't want to print them with PLA. Actually, first when I printed this with arachne perimeter generator in Slicer it was even more rounded so I had to change that to classic. Be warned. That version didn't stay on the limb at all.

Oh, and to first one I tried to black the line with permanent marker and that just bled black ink everywhere along layer lines, so use some other kind of color when using PETG.