Countermark

https://rpc.ashmus.ox.ac.uk/countermark/968 
GIC 850 ii
Κ Κ
rectangular incuse 
3 x 1mm 
on silver coins 

Coins with this countermark

Number Image TypeNumber CoinNumber VolumeNumber
RPC I, 3638A Show 3638 2 1
RPC I, 3638A Show 3638 1 1
RPC I, 3638 Show 3638 1 1
RPC I, 3638 Show 3638 2 1
RPC I, 3638A Show 3638 3 1