AUSTRIA: Karl VI, 1711-1740, AR thaler, "1721", KM-1594, Dav-1053, Hall Mint issue, four small flan flaws to left of portrait, mount expertly removed, lightly toned, EF.
This is a modern made piece from Bavaria circa 1900 for using for jewelry, especially for Bavarian traditional clothing and known as "Trachtenketten" or "Charivari". They were made of silvered brass and the letters are very modern comparing with old thalers. They were likely produced by Lauer in Nürnberg.
Estimate: 100-130 USD