Dog tags
thingiverse
This is a fully customizable dog tag that I made on my own, as it's very small (50x30x3 mm) you can put the infill at 100%, use PLA or whatever you want to. If you don't know how to remove letters from designs, I'll post a clean version of the tag.
Download Model from thingiverse
With this file you will be able to print Dog tags with your 3D printer. Click on the button and save the file on your computer to work, edit or customize your design. You can also find more 3D designs for printers on Dog tags.