Watch List notes:

MACEDON, Chalkidian League. Olynthos. Circa 425-420 BC. Hemiobol (Silver, 7 mm, 0.30 g, 12 h). Laureate head of Apollo to left; border of dots. Rev. ΧΑΛ - ΚΙ Tripod; all within incuse square. Robinson & Clement Group C, a–e and pl. II, 6. Very well-centered, sharply struck and nicely toned. Some minor traces of corrosion, otherwise, about extremely fine.
From the "Collection sans Pareille" of Ancient Greek Fractions.