A nice piece.
An undescribed variety in Kopicki with POLOI error.
Obverse: in the pearl rim the coat of arms of Elblag, in the outer rim the legend:
COIN:CIVIT:ELVI;
Reverse: in the pearl rim a shield with a crowned eagle, in the outer rim legend:
KASIMIRVS:R:POLOI;
Silver, diameter 19.8 mm, weight 1.34 g.