Watch List notes:

IONIA. Uncertain mint. 5th century BC. Tetartemorion (Silver, 5 mm, 0.14 g). Corinthian helmet facing to left. Rev. Quadripartite incuse square. Cf. Rosen 109 (Skione; obol). Cf. SNG Kayhan 743 (obol). Well centered. Earthen deposits, otherwise, very fine.