Not just a piece of rubber y'know...
...Oh no, it's a fully fledged, state-of-the-art Power Balance Band™©® folks, as reported here in this BBC news article showing a number of recently-victorious England cricketers wearing the latest piece of must-have new-age claptrap. http://www.bbc.co.uk/news/magazine-12135402
Although that article makes it fairly clear that the bands are pure placebo (although personally I think even that is being generous with language) a quick ramble through cyberspace produces a number of other articles which are far less critical of the outrageous quackery at the heart of this product. I would argue that for a supposedly reputable news outlet even to 'question' such products, is to already give the charlatans a credibility and legitimacy that they do not deserve.
At £30 a pop, the manufacturers of the band (who are clever enough to employ the sort of vague, ambiguous marketing so beloved of the same people who market homeopathy) must be making a killing from the section of society who are gullible, ignorant and faddish enough to cough up. Part of me thinks that such suckers deserve to be parted from their presumably hard-earned money... But another (stronger) part of me is filled with revulsion at what appears to be the fleecing of people, and I feel a sense of injustice at something which should, ideally, be prevented.
Unlike homeopathy, it's not as though the health of people is being directly jeopardised... So why should we even care so much?