Watch List notes:

EGYPT, Alexandria. Nero. AD 54-68. BI Tetradrachm (24.5mm, 13.40 g, 12h). Dated RY 13 (AD 66/67). Radiate bust left, wearing aegis; L IΓ (date) below chin / ΣEBAΣ[TOΦOPO]Σ, corbita with helmsman under sail to right; two dolphins in water. Köln 186; Dattari (Savio) 264; K&G 14.99 corr. (obv. legend); RPC I 5296; Emmett 121.13. Toned, flan flaw on Nero's neck, reverse struck slightly off center. VF.

There appear to be two different varieties of this type – one with dolphins and one without. Most likely, it commemorates Nero's visit to Greece in AD 66-67.