A nice piece.
Obverse: bust of Caesar wearing laurel wreath, armor and paludamentum, to the right, in the rim legend:
CONSTANTINVS MAX AVG;
Reverse: two soldiers standing at the sides of the banner, surrounded by legend:
GLORIA EXERCITVS; in section SMALA;
Bronze, diameter 14 x 15 mm, weight 1.5 g, axis 12 h.