The products were developed by Professor Svetlav Danev (Chief of the Department of Health & Safety in the
Bulgarian National Centre for Hygiene, Medical Ecology and Nutrition) who has
spent many years in the assessment of and protection from electromagnetic (EM)
effects on the working population. During the 'Cold War', he led a research team developing protection for senior politicians against possible psychotropic EMR attacks.
He developed a series of artificially grown crystals that were shown to reduce the effects of EMR on electrosensitive individuals. This is now available as the Biophone and Bioguard.
The smaller Biophone is attached to the phone and works when the phone is near the body.
The larger Bioguard is intended to be worn as a pendant or on a charm bracelet or keychain.
Both seem to protect against all forms of harmful EMR.