Strange 5.56 casing

I have had this casing in my collection for a long time, unfortunately I have no information on it.

It’s marked IVI 5.56 06. Any information or leads would be appreciated very much.

By the way this is my first post so sorry if it’s in the wrong section or is not correct in any way.

Once again thanks for any help identifying this round.

https://simunition.com/en/products/fx_marking_cartridges

Thank you so much!