Istros, Thrace, AR drachm, 19 mm, 5.03 g. 

Two facing male heads, the right inverted.
ISTRIH, sea-eagle standing left on dolphin.

Theta beneath eagle's wing, S dot beneath dolphin. 

Dima I-III-12.

With permission of Numismatik Naumann auction 86, Lot 52, Feb. 2020.