Any idea how the Bug Walt put on Hank's computer worked?

Hey there, i was just rewatching an episode of Breaking Bad, and it happened to be the episode where they find the barrel of methylamine with the tracker on it. Upon finding the tracker on the bottom of the barrel, Mike leads the group to believe that Lydia planted it to get them to stop using her as a source. When Mike makes it clear that he's certain that it wasn't the DEA who placed it there, they have Walt bug Hanks computer with that little black stick (with the red light on it) and the thing he placed behind the photograph of him and Marie. Back to my question, what kind of spying device/bug is this? How would you imagine it would work? And where would i be able to find one like it? I dont really have any plans to bug someone, i just think it would be a neat thing to have. Does anyone have any idea where to purchase something like it? Or have any idea what something like this would technically even be called. I've looked, and had no luck finding anything even remotely similar. Anyways, any answer will help. Would very much appreciate it. And no, i do not intend on using this to commit crimes. Thanks WF

TLDR: How does the spy device they planted on hanks computer/photograph work? and where can i buy one?

Submitted October 31, 2017 at 02:43PM by WilfyFrodo http://ift.tt/2z1occj