Countermark

https://rpc.ashmus.ox.ac.uk/countermark/875 
GIC 741
[L?] XVI
rectangular 
7 x 3 mm 
Legion XV Apollinaris. Might also have been applied at Tyana (Cappadocia). 

Coins with this countermark

Number Image TypeNumber CoinNumber VolumeNumber
RPC IV, 10689 (temporary) Show 1636 5 4.3
RPC IV, 5741 (temporary) Show 1797 11 4.3
RPC IV, 10689 (temporary) Show 1636 2 4.3
RPC IV, 10689 (temporary) Show 1636 4 4.3
RPC IV, 10689 (temporary) Show 1636 3 4.3
RPC IV, 5742 (temporary) Show 1803 13 4.3