Countermark

https://rpc.ashmus.ox.ac.uk/countermark/649 
GIC 522
ΓΑ | Γ
square 
5.5 mm 
Gaius, year 3 

Coins with this countermark

Number Image TypeNumber CoinNumber VolumeNumber
RPC I, 4272 Show 4272 3 1
RPC I, 4264 Show 4264 7 1
RPC I, 4273 Show 4273 10 1