Hey folks. A friend and I were having a discussion on Fallout doctors and we were stumped by a device that seems to be on most doctors in the wasteland, including James from Fallout 3 and Arcade from New Vegas, to name a few. Here's a picture of what I'm talking about: http://i10.photobucket.com/albums/a125/ArtemisPanthar/falloutdoctor.png

I was hoping that someone here might be able to provide some insight into what it is (it's probably something obvious that I'll kick myself for not noticing). It just seems to go into a pocket so I don't know what the other end of the device looks like. Perhaps its some sort of stethoscope? A blood pressure device? Battery pack of some sort? We're not sure! Any help you can provide will be appreciated, even just speculation

P.S. Please don't say "some kind of high tech/futuristic device," we know its something like that ;D

It's not explained.