It's the Iron Shell you get as a reward from reaching rank 5 in Iron Banner (TTK). Before, it was a light forest green with gray trimmings. For some reason, it looks just like the Starter Shell you get at the beginning of the game now, only with the crowned corners at the top and bottom. What happened? I'm not sure if the same thing happened to anyone else. (The picture is just for visual reference; just picture it with the crowned corners on the top and bottom.)