Can someone PLEASE tell me the technical name for the large battery-like device that sits atop a players helmet? The device appears very clunky and is basically a brick. I can't find one ANYWHERE to purchase, yet I see nearly HALF of aesthetically driven players with one on. Please forgive my ignorance but I'm beyond frustrated trying to even find the technical name for such a device. P.S. I don't care if the device is just for show, becuase I would like it to be an addition to my gear loadout. Thank you.