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.
I liked the way Blocsock implemented this protection and the quality of the product construction, combined with the validated test results, so I recently ordered ones for the rest of my family. I think Blocsock is the BMW-class of what I could find for products that protect against cell phone radiation. My wife has a larger Droid phone and it fits in the case (just barely though)! I hope the makers consider making a larger model for all the new, larger smartphones that recently came out with the larger screen sizes. Again, check to make sure your phone fits, which a friendly message to the company will answer if you are not sure.
This is why it’s important to always use either your phone’s speakerphone or an appropriate wired earpiece whenever possible, avoiding direct contact between your phone and your ear or hand. The best earpieces are those equipped with hollow tubing between the antenna in the wire and the earpiece, as these help maximize the distance between the radiation-emitting antenna and your head.
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).