The BlocSock is a small, 3”x5½”, lightweight case that's only designed for cell phones, not tablets or laptops. One side is a normal fabric to ensure reception. The other side has a rectangular, metallic mesh to shield RF radiation. It's recommended that you keep the side with the shielding material between the phone and your body. When making or receiving calls, keep the shielding between your head and the phone. It can also be moved into a smaller “kangaroo style” pouch during calls. It's effective, and tests show that it reduces RF exposure 96%. For more information, check out the SAR research test or watch this video.
In 2007, Dr Devra Davis founded nonprofit Environmental Health Trust to provide basic research and education about environmental health hazards. Dr Davis served as the President Clinton appointee to the Chemical Safety and Hazard Investigation Board in the U.S.A. from 1994–1999, an independent executive branch agency that investigates, prevents and mitigates chemical accidents.
Radiofrequency radiation is a form of electromagnetic radiation. Electromagnetic radiation can be categorized into two types: ionizing (e.g., x-rays, radon, and cosmic rays) and non-ionizing (e.g., radiofrequency and extremely low frequency, or power frequency). Electromagnetic radiation is defined according to its wavelength and frequency, which is the number of cycles of a wave that pass a reference point per second. Electromagnetic frequencies are described in units called hertz (Hz).