Independently tested DefenderShield technology uses a patent-pending 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 up to eliminate all radiation emissions from 0 to 10 GHz.

Instead of more animal and even epidemiological studies, he thinks researchers should focus on finding the mechanisms by which cellphone radiation may affect human health. Since we’ll never have an RCT on cellphones and cancer, he added, studies should measure actual cellphone use and exposure to radio-frequency radiation, instead of estimations of how much people are exposed (which most studies currently do).

Scientists have reported adverse health effects of using mobile phones including changes in brain activity, reaction times, and sleep patterns. More studies are underway to try to confirm these findings. When mobile phones are used very close to some medical devices (including pacemakers, implantable defibrillators, and certain hearing aids) there is the possibility of causing interference with their operation. There is also the potential of interference between mobile phones signals and aircraft electronics. Some countries have licensed mobile phone use on aircraft during flight using systems that control the phone output power.

There is only one legitimate method of measuring cell phone radiation recognized by every major health authority and government in the world as well as by the cell phone industry itself, referred to as "SAR". SAR testing measures the "Specific Absorption Rate" of radiation at multiple depths and locations on the head and body in order to quantify how much radiation is actually penetrating it with and without certain safety devices. You can see a SAR test of the R2L device by watching the video below.

The phone is placed in various positions on the head and body, including held to both ears, and all measurements are taken and reported to the FCC when the manufacturer is seeking approval. However, it should be noted that only the very highest SAR values for each type of radiation are included in final consideration for compliance with the FCC’s guidelines.

There is great variability in survival by brain tumor subtype, and by age at diagnosis. Overall, the 5-year relative survival for brain cancers diagnosed from 2008 through 2014 was 33.2% (49). This is the percentage of people diagnosed with brain cancer who will still be alive 5 years after diagnosis compared with the survival of a person of the same age and sex who does not have cancer.

The tricky part about measuring the radiation from a cell phone is that the emission strength varies widely over time. There will be strong bursts of varying intensity, followed by quiet periods. This makes it hard to compare "apples to apples". Also, because you are measuring up close to the source, you must use a near field meter AND you must maintain the position of the meter very precisely.

With our Phone Pouch, you can carry your phone at a safer distance. And with our powerful shielding material that lines the back of the Phone Pouch and deflects up to 99% of cell phone radiation (65-80 dB attenuation of frequencies from 30MHz to 1GHz), you’re exposed to even less harmful cell phone radiation. Our Phone Pouch uses well established science– inside each Pouch is a layer of fabric, interwoven with gossamer thin metallic threads that form a shield to deflect EMF radiation, working much like a Faraday cage.

Mobile phones emit radiofrequency energy, a form of non-ionizing electromagnetic radiation, which can be absorbed by tissues close to the phone. The amount of radiofrequency energy a mobile phone user is exposed depend on many factors as the technology of the phone, the distance between the phone and the user, the extent and type of mobile phone use and the user’s distance from cell phone towers. (2)

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.
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. 
The frequency of radiofrequency electromagnetic radiation ranges from 30 kilohertz (30 kHz, or 30,000 Hz) to 300 gigahertz (300 GHz, or 300 billion Hz). Electromagnetic fields in the radiofrequency range are used for telecommunications applications, including cell phones, televisions, and radio transmissions. The human body absorbs energy from devices that emit radiofrequency electromagnetic radiation. The dose of the absorbed energy is estimated using a measure called the specific absorption rate (SAR), which is expressed in watts per kilogram of body weight.