A nice piece of a rare and sought-after issue. Patina, tarnish.
Obverse: emperor's head in laurel wreath, clockwise, in the rim legend:
IMP CAE L SEP SEV PERT AVG
Reverse: legion insignia, in segment TR P COS legend, in rim legend:
LEG VIII AVG
Silver, diameter 17.2 mm, weight 2.79 g, axis 5 h.