Istros, AR triobol, 1.65 g.

Two male heads facing, the left inverted.
ISTRIH, sea-eagle left on dolphin.
One dot under the eagle's head, one dot under the eagle's 
tail, Delta beneath the dolphin.

Canarache 348; Welz 27 in Schweiz.Münzbll. VII (1957); 
Bloesch 12 in "Das Winterthurer Münzkabinett 1948-1958".

Image is from the Bloesch article.
Note: what appears to be a dot beneath the dolphin, 
making the Delta look like a Z is just part of the dolphin.
 
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