Q-Link Products

Hi,

I was wondering if anyone has an opinion on these types of energy products that are becoming more popular:

http://www.qlinkproducts.com/Scripts/default.asp

They are pendants that you wear around your neck and which are supposed to strengthen and enhance your energy / chi. The makers claim they have scientific support for these claims. There is an explanation of how they are said to operate here:

http://www.qlinkproducts.com/Scripts/openExtra.asp?extra=137

Does anyone know if they actually work? For someone practicing Qigong are they unneccessary? I have heard some people say that they may be harmful as they interfere with the natural interplay of the body's energies and amplify some at the expense of others.

Any thoughts / comments?
Jim.