It seems like it's mostly made up of computer chips. There's something which looks like an internal battery, yes. It doesn't look like there's a literal tracking bug in there or anything, but it could always be a program, so it's difficult to tell if they're being tracked via the tablets or not.

As soon as they start pocketing and swallowing things, they will both feel a small, sharp sort of pain on their backs, like that of a needle, and they will drop to the ground, unable to move or feel anything. The tablet's recording is shut off, though not before there can be seen something shuffling around under and through their clothes. They will remain stuck like this, conscious but numb and staring up at the ceiling, for twenty minutes, when the feeling will begin to subside. All of the chips left on the ground are gone, and the ones in their pockets are gone. There are a few scattered flecks of blood on the inside of their shirts.

The scars left just above their stomachs will fade in approximately an hour.