Looks like it's maby the edge 2 tail light?
There are lots of options out in the aftermarket world. Although that one fits nicly. Got a pic of the whole bike with that?
If you don't want to order, you can get it from Kimpex, which alot of dealers sell from kimpex. UFO has a few options, as well as enduro engineering has some tail lights.
If there are any enduro, or european dealers in your area (aprilla, Gas gas, Husaberg, KTM, husky), I would try there first to see if they stock anything.