Istros, Thrace, AR Drachm, 17mm, 5.25 g. 4th C. BC. 

Two male heads facing, the right inverted.
ISTRIH, sea-eagle left on dolphin, DTB monogram beneath eagle's tail. 
Unpublished monogram. Pecunem 24, lot 52.

With permission of Pecunem Gitbud & Naumann Auction 24, Lot 52, Nov. 2014.