The outside is made of a synthetic polyurethane that feels just like leather, although genuine leather will be available soon. The inside is made of a microfiber that won’t scratch the phone. The materials are also designed to protect your phone, should you drop it. Most importantly, an integrated FCC-certified lab tested radiation-shielding foil not only deflects and absorbs RF, ELF and Thermal radiation to greatly reduce your exposure, but it also blocks RFID signals, so that hackers cannot steal your credit card information by scanning it from afar. And no, the case will not affect phone or battery performance.
The ultra thin (1mm) RadiCushion by Cellsafe slips into the cell phone case and redirects radiation away from the face of the phone. It's available in black or white but not recommended for use with aluminum or metallic cell phone cases. Test results show a SAR reduction of 96%. A slightly thicker (2mm) RadiCushion is available for iPad and iPad mini; it adheres to the back of the device and also provides SAR reductions of 96%. Visit their website for more information or watch this independent test which shows an 80% reduction and also compares it to the BlocSock:
DefenderShield Cellphone Radiation Case also claims independent testing and says in their website: That a "sophisticated layering of separate non-toxic, human safe materials processed for maximum radiation blocking efficiency. Each material has unique and targeted radiation-shielding characteristics designed to work in unison to eliminate all radiation emissions from 0 to 10 GHZ and Defender Shield technology refracts, conducts and finally absorbs all these potentially harmful emissions."  In this demonstration, the radiation level measured when DefendeShield case was on is still quite a bit above the level of exposure that I would recommend. I personally do not recommend-holding a phone with a shielding case to your head as the DefenderShield website shows a young woman doing as she demonstrates the product. 

Says Dr. Carlo: “We also conducted four different epidemiological studies on groups of people who used cell phones, and we did clinical intervention studies. For example, studies of people with implanted cardiac pacemakers were instrumental in our making recommendations to prevent interference between cell phones and pacemakers. In all, we conducted more than fifty studies that were peer-reviewed and published in a number of medical and scientific journals.”
The Specific Absorption Rate that the FCC, with input from many other government institutions, decided on, is defined using an average of a 30-minute phone call with the cell phone held directly to the ear. Since modern cell phones are used in all sorts of manners, ie speakerphone, scrolling through social media, browsing the web, etc, a base had to be set.
The studies are notable for their sizes. Researchers at the National Toxicology Program, a federal interagency group under the National Institutes of Health, tested 3,000 rats and mice of both sexes for two years—the largest investigation of RF radiation and cancer in rodents ever undertaken in the U.S. European investigators at the Ramazzini Institute in Italy were similarly ambitious; in their recent study they investigated RF effects in nearly 2,500 rats from the fetal stage until death.
5. Use an EMF shielding device. A variety of holsters and other cell phone holders and shields are available that claim to block radiation. If you buy such a product, look to see if it has an SAR (specific absorption rate) value. You want a shielding device that blocks the majority of EMFs. (SAR is a measure of the rate at which energy is absorbed by a body exposed to EMFs.) 
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The base station is equipped with antennas for reception and transmission. In order to communicate, the mobile phones and the antennas at the base station emit radiowave radiation (see below). The mobile phone instrument transmits a lower amount of radiation than the one transmitted by the transmission center (cell site), but because the instrument is near the body, the body directly absorbs the energy from the instrument’s antenna.
I did a lot of research prior to purchasing and came down to this one as the best/most tested and proven option. Happy with the cover. I don’t have a way to actually test the efficacy of it but it’s a quality product otherwise. I haven’t dropped it but there’s enough room around the edges that it seems like it would have a good cushion to blunt the impact when I do. I’d recommend trying it if you like the looks of It.

George Carlo, PhD, JD, is an epidemiologist and medical scientist who, from 1993 to 1999, headed the first telecommunications industry-backed studies into the dangers of cell phone use. That program remains the largest in the history of the issue. But he ran afoul of the very industry that hired him when his work revealed preventable health hazards associated with cell phone use.
Specific Absorption Rate (SAR) is an indicator for calculating the level of radiation absorbed in the body. This indicator represents the rate of energy absorption by the tissue and is expressed in units of Watt/kg. The Consumer Protection Regulations (information on non-ionizing radiation from mobile phones) of 2002, stipulate the duty to label the product, specifying the radiation level of the phone’s model and the maximum permitted radiation level. This regulation allows to compare the emitted radiation level between different instruments and to take this into consideration when weighing the factors determining the choice of a new instrument at the time of its purchase.
The International Agency for Research on Cancer (IARC) is part of the World Health Organization (WHO). Its major goal is to identify causes of cancer. The IARC has classified RF fields as “possibly carcinogenic to humans,” based on limited evidence of a possible increase in risk for brain tumors among cell phone users, and inadequate evidence for other types of cancer. (For more information on the IARC classification system, see Known and Probable Human Carcinogens.)

According to the WHO, the "precautionary principle" is "a risk management policy applied in circumstances with a high degree of scientific uncertainty, reflecting the need to take action for a potentially serious risk without awaiting the results of scientific research." Other less stringent recommended approaches are prudent avoidance principle and as low as reasonably practicable. Although all of these are problematic in application, due to the widespread use and economic importance of wireless telecommunication systems in modern civilization, there is an increased popularity of such measures in the general public, though also evidence that such approaches may increase concern.[35] They involve recommendations such as the minimization of cellphone usage, the limitation of use by at-risk population (such as children), the adoption of cellphones and microcells with as low as reasonably practicable levels of radiation, the wider use of hands-free and earphone technologies such as Bluetooth headsets, the adoption of maximal standards of exposure, RF field intensity and distance of base stations antennas from human habitations, and so forth.[citation needed] Overall, public information remains a challenge as various health consequences are evoked in the literature and by the media, putting populations under chronic exposure to potentially worrying information.[36]
The guidelines created a measure of the rate that body tissue absorbs radiation during cell phone use called the specific absorption rate (SAR). The SAR for cell phone radiation was set at a maximum of 1.6 watts of energy absorbed per kilogram of body weight. The limit was set due to the thermal effects of cell phone radiation (all RF radiation can heat human body tissue at high enough levels) - it was not set to mitigate other biological effects cell phone radiation might have such as DNA damage or cancer.
An analysis of data from all 13 countries participating in the Interphone study reported a statistically significant association between intracranial distribution of tumors within the brain and self-reported location of the phone (7). However, the authors of this study noted that it is not possible to draw firm conclusions about cause and effect based on their findings.