Helena, AE3, 325-326, Nicomedia, 18.4mm, 3.028g. 

FL HELENA-AVGVSTA, mantled bust right, wearing diadem as broad band decorated with a single string of pearls.
SECVRITAS-REIPVBLICE, Securitas standing facing, head left, 
branch downward in right hand, raising robe with left. 

Mintmark SMN Gamma. 
RIC VII Nicomedia 95, rated R2.

Contributed by Online Store of the Forum Ancient Coins, Sep, 2011