I use my cellphone only on emergencies. When I do use my cellphone, I use it with a wired Air tube earpiece or while on the speaker. I do however think these products might also improve the reduction of the radiation to the user. It is still not a ALL OK to use the cellphone as much as you like and please remember to turn 3G/4G data and WIFI off at all time.
I did not test this item but the logic behind it seems to be good. The Radiation Blocker is installed inside the cover that is hold down between the side of the face and the phone, redirecting some of the RF radiation away from the user.