Countermark

https://rpc.ashmus.ox.ac.uk/countermark/646 
GIC 519
Β, Ι with • on it, Β
circular 
10 mm 
on Tiberian dupondii 

Coins with this countermark

Number Image TypeNumber CoinNumber VolumeNumber
Show 214
RPC I, 3868 Show 3868 32 1