Countermark

https://rpc.ashmus.ox.ac.uk/countermark/849 
GIC 728
XF
rectangular 
6 x 4 mm 
The cmks may belong to GIC 727 or form a distinct group. 

Coins with this countermark

Number Image TypeNumber CoinNumber VolumeNumber
RPC I, 4834 Show 4834 16 1
RPC I, 4834 Show 4834 13 1