Countermark

https://rpc.ashmus.ox.ac.uk/countermark/900 
GIC 770
denominational mark Β
circular 
5 mm 
sometimes on reverse; applied with GIC 125, sometimes on same side, other times on different sides 

Coins with this countermark

Number Image TypeNumber CoinNumber VolumeNumber
RPC III, 4099 Show 4099 55 3
RPC III, 4099 Show 4099 54 3
RPC III, 4099 Show 4099 56 3
Show 135
Show 441
Show 215
Show 2
Show 444
Show 445
Show 447
Show 446
Show 333
Show 454
Show 453
RPC III, 4099 Show 4099 65 3
Show 192
Show 193