non-US World War I Dog Tags
Dog Tags are not a American invention  other countries use them also, here are several examples .

This Yogoslavian example donated to military-dogtags by Richard Dona of  The Netherlands is a wonderful example of the locket style favored by most eastern european countries during the Great War.

A Czarist Russia, WWI , copper, 50mm, 6-sided,
with cyrillic inscription. Said to be found at
the 1914 Tannenburg site.

A French WWI bracelet id tag

Two British WWI ,brass, Dog Tags

An Austrian WWI brass locket with paper information inside
with the owners name engraved on the outside
A very rare piece.