Can two spools shield you effectively against radiation a friend of mine thinks that by buying a product called rayguard he can effectively shield against electrosmog.
On the website, there are multiple evidences that this might work. However the product seems to be just created of one plastic chasis with two spools inside. The functionality of the product is described as following:

With the RayGuards, the solution therefore is not based upon
  electronics but on physics. In a radius depending on the model of
  device used, all frequencies are absorbed.
This spectrum of frequencies is being put through a dividing and
  analysing system. There the compen- sation of the harmful waveparts is
  made.
To explain it better, we will use the example of a camera. Compare the
  effect of the RayGuard to the polarising filter. Disturbing effects of
  reflection are being cleared by the filter and the foto looks clear
  and colourful again.

I do not claim that I am a physicist , however after some research my personal opinion on this product is that it is not so simple to shield against radiation. My questions to you are:


*

*Is it possible with the rayguard to shield effectively against radiation? If it is a scam? Why "not"

*From a physical standpoint, how to shield properly against radiation? What device would be needed to shield effectively against for example mobile phone radiation

*Is the everyday radiation from a physical standpoint "unhealthy"?


I really appreciate for your reply!
PS.: I know that this question is not the typical physics question which is asked here, however it would be great if you could give me some hard facts/theories to prevent my friend from wasting a lot of money!
 A: Whether or not shielding against radiation is possible depends on the type of radiation. As an example the perforated metal shield in the front of a microwave oven is pretty effective. This type of radiation is called electromagnetic radiation . At lower frequencies it becomes radio waves, at higher frequencies light. At still higher frequencies we encounter X-rays, and at even higher frequencies, $\gamma$-radiation.
X-rays and $\gamma$-radiation are dangerous, for X=rays lead is a useful shielding material. There also exists $\beta$-radiation (electrons) and $\alpha$-radiation (atomic nuclei).
The "Rayguard" you mention is likely not to work. Even if there is electronics involved it must be able to detect all frequencies of interest. This is pretty hard if not impossible to do so in the X-ray regime. In my opinion this rayguard is on the same level as the boxes that protected against "earth rays". There the scam was even more severe, earth rays are not supposed to exist.
About radiation from mobile phones being harmful opinions differ. Their radiation can be rather persistent. I have seen a demonstration with one such phone placed in a metal box 
as used for biscuits. When connecting to it from a second phone outside the box it still responded. Of course the radiation level inside the box is very low but still it was large enough to let the phone ring. 
