Germany, Luftwaffe. A Pilot And Observer Badge, By Friedrich Linden certificate_of_authenticity His service papers note that

His service papers note that a duplicate China medal was issued in May 1907 to replace the one lost in a Railway accident on 3 January 1907

with a small chip adjacent to the second row of the tightly wrapped twisted brass wire

Footnote: The medal was instituted on July 4

1878 during the reign of Alexander II

An prime example

Germany, Luftwaffe. A Pilot And Observer Badge, By Friedrich Linden certificate_of_authenticity His service papers note that(Beobachter und Flugzeugfhrerabzeichen). Constructed of gilded and silvered feinzink, the obverse consisting of an oval laurel and oak leaf wreath, joined together at the bottom by ribbon, overlaid by a swooping Luftwaffe eagle clutching a hand filed mobile swastika, the reverse with a barrel hinge and vertical pinback meeting a flat wire catch, with two visible rivets holding the obverse eagle in place, unmarked but with the physical characteristics