It's to carry US 3 shells for mortar.
When in good condition, there is a white marking. don't clean it because it's easy to find.
Can I find any pictures of it from war time? If you know any
If you really found it in Foy, leave them for what they are...... just for yourself
I also have some found stuff , and I keep it as is.....
btw, deleted your other (double) thread
Here`s a picture of them...
JEDEM DAS SEINE