Pure snake oil, like many sensor cleaning products.
My guess is it's basically the same material as used for ESD mats. And what it's supposed to do by just putting a camera on it, I have no idea. No mention of size, but probably about 10" in diameter, and what a bargain at $35. And I sure wouldn't want to place a digital device on a magnet big enough to have any sort of effect.
PT Barnum is alive and well...