I recently picked up a movie called The Tournament (trailer), which is an action movie in the same vein as Battle Royale and The Running Man.
In the movie, there are tracking devices that are used for not only the people betting on the killers to track them, but allow for the killers to track down and kill each other. For some reason, I think I've seen the casing they used for the scanner somewhere before, but I can't figure out where. It looks like they took a couple of smart phones and redocrated them, but I can't be sure. Any ideas on what they are?
Here are some screencaps of the device. Since the back of the device isn't featured clearly, all I can say that it has a mirror-like surface on the very back, where there's a small hole that looks almost like the back of an iPhone with a camera built in.
(NOTE: I noticed that for this one, it has a different "face" on the bottom for this shot and top. The one scene here, which shows up in one scene with Lai Lai uses it, but is not the one she is seen using in scenes before this one, one of them pictured below, the last screencap is from the first scene we see this device. Later on in the movie, it switches back to the one she started with and again, for one shot much later, switches back to this one. However, another character is seen with this particular one)