Constantine II AE follis of Constantinople. AD 337-340. 

DN CONSTAN-TINVS PF AVG, laureate head right.
GLOR-IA EXERC-ITVS dot, two soldiers holding spears and shields with one standard between them.

Mintmark CONS Theta.

RIC VIII Constantinople 23; Sear 17437; Freiburg 8520.
Rated Rare. 

Image courtesy of the Seminars für Alte Geschichte der Albert-Ludwigs-Universität, D-Freiburg

Note: RIC rates RIC 23 as common, but there are none on CoinArchivesPro, acsearch and only 4 on the ANS OCRE website.