Watch List notes:

Egypt, Alexandria. Faustina II. Augusta, A.D. 147-175. AE obol (17.9 mm, 3.93 g, 11 h). Dated year 19=A.D. 155/6. ΦAVCTINA CEBACTH, draped bust right / [L IΘ], Sphinx seated right with paw on wheel. Milne -; Emmett 2036. Fair. Very Rare. 

Emmett lists this coin with a rarity rating of 5 (extremely rare) and lists the date as "19?". The date on this specimen isn't clear either. One of only a few known.