Lot #301), but in that auction it was listed as a tetrobol. The size is 13 mm, weight is 2.66 g. I noticed there is a lot of overlap in the size and weights of the drachms, tetrobols and diobols of this common type of AR coin from Apollonia. Many share the same type of obverse, reverse, and reverse control marks. Seems like that would have created a lot of confusion in the marketplace back then. Is there a reliable way to distinguish drachms, tetrobols, and diobols of this coin type, or is it just a best guess based on size and weight? Thanks for your expertise. THRACE, Apollonia Pontika, ca.425-375 B.C.. AR tetrobol, Attic standard. Obv: Facing Gorgoneion, with tongue protruding. Rev: Upright anchor; A under left fluke, crayfish under right. SNG Bulgaria 306 (same rev. die). 13mm, 2.66 g.