Countermark

https://rpc.ashmus.ox.ac.uk/countermark/651 
GIC 524
ΓΑ | Ɛ
rectangle with rounded corners 
6 x 4 mm 
Gaius, year 5 

Coins with this countermark

Number Image TypeNumber CoinNumber VolumeNumber
RPC I, 4264 Show 4264 5 1
RPC I, 4272 Show 4272 18 1
Show 300
RPC I, 4264 Show 4264 16 1