when we received this photo in our inbox, our initial reaction was a glow-in-the-dark dummy mortar round and we are right. There are other products to be released by Milsim Labs and they will have the tracer grenades ready this December with the Mortar rounds and hand grenades that also glow by next year. Hopefully you don't have to light them up before firing them since you will give away your position carrying these rounds around.
We don't know yet how these will work, but we sure are looking forward to knowing more. So Milsim Labs, don't scrimp on information, send us more, say a video.