*SAR values are from tests conducted by Pong Research Corp on March 29, 2012 and submitted to the FCC on May 31, 2012. Because the SAR values were submitted to the FCC in graph form, EWG estimated numerical SAR values based on the chart available in WT Docket 11-186 (http://apps.fcc.gov/ecfs/document/view?id=7021921006). Pong’s filing to the FCC did not indicate whether SAR measurements were done at the head or in a body-worn configuration. In a personal communication, Pong informed EWG that the SAR measurements were done in a body-worn configuration, with the same distance from the test mannequin used by the phone manufacturer. Tests in the body-worn configuration were done at a 10 millimeter separation distance.
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. 
Several national and international agencies study different exposures and substances in the environment to determine if they can cause cancer. (Something that causes cancer or helps cancer grow is called a carcinogen.) The American Cancer Society looks to these organizations to evaluate the risks based on evidence from laboratory and human research studies.

The Working Group indicated that, although the human studies were susceptible to bias, the findings could not be dismissed as reflecting bias alone, and that a causal interpretation could not be excluded. The Working Group noted that any interpretation of the evidence should also consider that the observed associations could reflect chance, bias, or confounding rather than an underlying causal effect. In addition, the Working Group stated that the investigation of risk of cancer of the brain associated with cell phone use poses complex methodologic challenges in the conduct of the research and in the analysis and interpretation of findings.
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.
I have not gotten a cell phone, I was gifted a tablet, but it stays off most of the time, I use a desktop PC and my home phone is still landline but cordless. For me it’s been a bit of mixed bag in that I don’t want to rely so heavily on technology to do and remember things for me. When I hear about the new and latest tech that can now do X,Y, or Z for you, I think of the two little boys in the 80’s Cafe in BTTF.

A study by the Corporate EME Research Laboratory and Motorola Florida Research Laboratories tested 9 different cell phone radiation shields, 5 of which claimed to block 99% of cell phone radiation. The other 4 shields tested claimed to emit a reverse radiation that would cancel out the harmful radiation from cell phones. The study found that all of the radiation shields had no effect on the amount of radiofrequency radiation a cell phone user is exposed to from their phone.[2]
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.