Watch List notes:

Gallienus. A.D. 253-268. BI antoninianus (22.1 mm, 3.05 g, 7 h). Rome mint, struck A.D. 253-254. IMP C P LIC GALLIENVS AVG, radiate, draped and cuirassed bust of Gallienus right / CONCORDIA EXERC, Concordia standing left, holding patera and double cornucopia. Göbl 16v; RIC 132; RSC 129. aVF, most silvering remains, slightly rough. Very Rare.

RIC records both the EXERC and EXERCIT reverse legends under RIC 132, however, the EXERC variety is exetremely rare. There are none to be found at ACSearch, CoinArchives, Wildwinds, or the Marcy Henderson collection of Gallienus coins at CoinProject. This coin is a must-have for any Gallienus specialist.