Countermark

https://rpc.ashmus.ox.ac.uk/countermark/956 
GIC 842
laureate bust r., letter before (Ϲ, Ο, or Κ) (on silver coins)
oval 
7 x 5 mm 
On silver coins, sometimes on reverse 

Coins with this countermark

Number Image TypeNumber CoinNumber VolumeNumber
RPC III, 3257 Show 3257 4 3
RPC III, 3257 Show 3257 71 3
RPC III, 3257 Show 3257 8 3
RPC III, 3257 Show 3257 5 3
RPC III, 3257 Show 3257 16 3
RPC III, 3257 Show 3257 10 3
RPC III, 3257 Show 3257 65 3
RPC III, 3257 Show 3257 2 3
RPC III, 3257 Show 3257 11 3
RPC III, 3257 Show 3257 86 3
RPC III, 3257 Show 3257 87 3
RPC III, 3257 Show 3257 89 3
RPC III, 3257 Show 3257 17 3