Krupp Kugelpanzer (Ball Tank)
German WW2 experimental mobile pillbox/reconnaissance vehicle. Crewed by a single man. This is not my work but a file I found and cleaned up. Scale it to your favorite scale. My best guess is it has an overall diameter of about 167.64 cm. or 5.5 feet
Here is a Wikipedia page for this:
https://en.wikipedia.org/wiki/Kugelpanzer
http://strangevehicles.greyfalcon.us/KRUPP%20KUGELPANZER.htm
Scale conversion chart link
http://www.wwi-models.org/misc/scalecon.html
one of the files is full size 1-1, the other is scaled at 1-100 if you need another scale use the scale conversion link to figure it out
The original file and work by the designer can be found here