I'm not overly convinced.
A study conducted on seven healthy men and three women between 26 and 36 years continuously measured blood pressure, heart rate, capillary perfusion, as well as subjective well-being in relation to mobile telephone electromagnetic fields (EMFs). The subjects were exposed to EMF waves from a cell phone in a fixed, typical position on the righthand side of the head.
They concluded that exposure of the right hemisphere to a radiofrequency EMF for 35 minutes causes and increase in sympathetic different activity with increases in resting blood pressure between 5 and 10 mm Hg, most likely due to more pronounced vasoconstruction
1. The cross-section of participants is low, considering the magnitude of mobile, (cellular), phone use.
2. The thing about resting blood pressure looks wrong to me. You probably know that Diastolic blood pressure is caused by the Heart resting for a brief moment, I doubt it can be influenced by Vasoconstriction, but I could be wrong, and even if it is, so would Systolic, as Vasoconstriction would temporarily restrict or slow down blood flow regardless.
Also some of the testimonials have people saying their symptoms from phone use have gone, but half mention nothing except supposedly watching documentaries, and being glad of the protection, but that doesn't mean they had a problem to begin with.
Also the tests look dubious.
The test results on their site are 8 years old, and one appears to use far more concentrated radiation than I suspect a phone user would get, (but I can't be sure on that), and the second espouses the possibility of a health risk. Enough to get you thinking, but not enough to be a concrete "beware" factor.
Also the test they did on the subjects was for 35 minutes. This is assuming most people in the current climate use them for at least that long. Many may use them for 20 minutes or less, or once every 2-3 days.
I feel in conclusion, it isn't a phoney product, but I don't see it as necessarily a must have, or a waste of money.
I'm in the middle on this.