Countermark

https://rpc.ashmus.ox.ac.uk/countermark/927 
GIC 811 iv
denominational mark Ϛ
circular 
6 mm 
probably applied at Ephesus, but not certain 

Coins with this countermark

Number Image TypeNumber CoinNumber VolumeNumber
RPC X, — (number not assigned), type ID 61391 Show 1699 1 10
RPC X, — (number not assigned), type ID 61190 Show 2014 1 10
RPC X, — (number not assigned), type ID 60897 Show 1756 2 10
RPC X, — (number not assigned), type ID 61513 Show 2041 2 10
RPC X, — (number not assigned), type ID 61092 Show 1900 9 10