I live near Nijmegen and i'm seaching often to things of WW2 with a metal detector.
For a short time ago, i went to a site where in WW2 a mortar stand was.
In the first hour i found already-ditched-up mortar/25pounder shell cases and other rubbish. But 3 feet beside a traffic road i found this beauty!
A British oil compass! It does still works!