A nice piece.
Obverse: bust of Caesar wearing laurel wreath, armor and paludamentum, to the right, in the rim legend:
FL IVL CONSTANTIVS NOB C;
Reverse: two soldiers standing at the sides of the banner, surrounded by legend:
GLORIA EXERCITVS-; in section CONSN;
Bronze, diameter 15.5 x 18 mm, weight 1.6 g, axis 12 h.