https://rpc.ashmus.ox.ac.uk/countermark/711 

GIC 585

CIC?

rectangular 

7 x 4 mm 

Sinope (Paphlagonia)

If CIC is read, the countermark may have belonged to Apamea (Bithynia) - Colonia Julia Concordia, but until further specimens arise, no additional specyu;ation is worthwhile. No other countermarked coin of Sinope is recorded.