So, in the “headcount” scene of The Avengers, Tony Stark puts on a pair of metal wristbands (let’s just call them bracelets, that’s what they are), and later uses them to put on the Iron Man suit. No big spoiler there, yes, Stark wears the Iron Man armor in The Avengers.
As it happens with movie props from time to time, instead of fabricating something new, they go out and find something that already exists and use that, or starts with a real world item and goes from there.
In Star Wars: Episode, Qui-Gon famously spent a lot of time talking into a Gillette For Women SensorExcel razor handle with some spare LEGO bits and parts from an unfinished Ikea computer desk glued on.


In Terminator 3, they crank up a particle accelerator with the throttle from a Saitek joystick:

So anyways, in The Avengers, Tony slaps on some jewelry, which turns out to be a pair of MAGTITAN NEO LEGEND Power Bands from Trion Z. They are made from titanium and stainless steel, decorated with carbon fiber and coated with a protective resin.
ThinkGeek (among other places) is now selling them.
So why is this a bad thing?
Well, “powerbands”, along with similar products, are compete bullshit products. They contain very strong magnets inside under the theory that their orientation will cause the magnetic field around you to shift, allowing for things like “more harmonious energy flow” in order to “increase vitality and wellness”.
You’ll notice words like “vitality” and “wellness” used when talking about these things, because they don’t actually mean anything. You can’t measure vitality. It’s a nonsense word in terms of science and health.
In fact, go to the Trion Z website and try to find any mention anywhere on the site about what their bands actually do. The closest they say is that there are magnetic fields everywhere and their bands create negative ions. They never make any claims about what those ions do or what benefit they have, because they aren’t allowed to. Any claim they make would have to be backed up by science, which simply does not exist for these sorts of things.
So what we end up with, through licensing deals now, is a company selling bullshit sham pseudoscience at $200 a pop is getting promoted by the biggest movie of the year.

And they are even making money off the kids:

Now I really wish someone had just bent some metal and made him new bracelets.