There are alternate technologies that can be considered when looking to reduce cell phone radiation exposure which we don’t use. Why don’t we use them? Incorporating technologies such as antennas into a case can greatly reduce outgoing cell phone radiation levels when close to the cell tower, but not totally. If farther away, the cell phone signal levels increase, as does the radiation exposure to the body, possibly to unacceptable output power levels. This design does not reduce radiation exposure from the WiFi and Bluetooth RF because cell phones do not have the capacity to reduce their power levels whether or not an antenna is present. Maybe just as important, this design does not have the shielding capacity for ELF emissions which have the same dangers as the RF emissions. Other device attachments like buttons and stickers are minimally effective to totally ineffective, with no scientific basis. In short, there are no other technologies capable of up to eliminating all of the many potentially harmful cell phone emissions from hitting the body.
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.
The energy of electromagnetic radiation is determined by its frequency; ionizing radiation is high frequency, and therefore high energy, whereas non-ionizing radiation is low frequency, and therefore low energy. The NCI fact sheet Electromagnetic Fields and Cancer lists sources of radiofrequency radiation. More information about ionizing radiation can be found on the Radiation page.