Constantine I, AE16, Cyzicus. 335-337 AD.

Obv: CONSTANTI-NVS MAX AVG, rosette-diademed, draped, cuirassed bust right.
Rev: GLOR-IA EXERC-ITVS, two soldiers standing beside
one standard with O on banner.
Mintmark SMKB.

RIC VII Cyzicus 122, rated R3.

From Dane's collection, Feb. 2011.

Listed mintmarks for RIC 122:
SMKA
SMKB
SMK gamma
SMK delta