Countermark

https://rpc.ashmus.ox.ac.uk/countermark/968 
GIC 850 ii
ΚΚ (on silver coins)
incuse 
 

Coins with this countermark

Number Image TypeNumber CoinNumber VolumeNumber
RPC I, 3638A Show 3638 2 1
RPC I, 3638A Show 3638 1 1