Countermark

https://rpc.ashmus.ox.ac.uk/countermark/772 
GIC 649
monogram IMP
rectangular 
Imperator; Pangerl 79 

Coins with this countermark

Number Image TypeNumber CoinNumber VolumeNumber
RPC I, 2235 Show 2235 48 1
RPC I, 5422 Show 5422 1 1