Prussia, Observer Badge. Type C.E. Juncker.

Tombak/brass based and in an excellent, probably unworn condition with all of the matt silver plate still present, the high points burnished and all with some patina. The enamel without damage.
Not marked but a known variation that has been attributed to the company of C.E. Juncker, Berlin. See Carsten Baldes, Abzeichen und Ehrenpreise der Fliegertruppe von 1913 bis 1920.
Difficult to find in such condition.