15mm M/54 Swedish Eldmarkering Cartridge

I show my two 15mm M/54 cartridges and ask what device they are used in?
I had a box marked Eldmarkering (?) from memory for the Czech SBP blue plastic one.
The paper one is earlier and marked: emarkptr. M/54. Blue paper.
Seems to be a 28ga shotshell size. Both are 32.2mm long.
Seems to be some marking cartridge used in Sweden.

The m/54 is used in tank fire simulators attached to the barrels of tank guns (outside) to be used during exercises.


And also used in the 84mm Carl Gustaf recoilless rifle:


Thank you EOD
I have had the cartridges for years and never knew the use till now.
Nice references. I did my first translation and learnt a lot.