Never heard of, but.. it says "creates a field of natural radiation around the phone."
Even if it does this, it still doesn't remove the original signal.. just adds another on top of it.
It's like, I'll feed you peanuts if you have peanut allergies, but I'll also mix anti-allergy pills inside.
Not to say that it doesn't work, but I'm not aware of any "natural" frequencies like it says. Natural background RF level is extremely low.. The best it could do is emit the Schumann frequency, but the level would be so overpowered by the phone itself, how would your body even 'hear' it?
Olle J. said he tested many of these type of devices and none of them do anything. It says he talks about it, and is curious to see the results, but does not say he endorses it.