Rare follis.
R2 in the Roman Imperial Coinage catalogue.
Roman Imperial
Constantine II (337–340) - as Caesar 317–337, Follis 324-325, Cyzicus mint
Obverse: laureate, draped and cuirassed bust left
CONSTANTINVS IVN NOB C
Reverse: camp gate with two turrets, without doors, star above, SMKB in exergue
PROVIDENTIAE CAESS
Diameter 19 mm, weight 3.16 g