While talking on your cell phone, prefer to position the cell phone away from your body as far as possible. Whenever possible, use the speakerphone mode or an airtube wired headset (not a wireless headset, not a wireless earpiece). The electromagnetic field (radiation) is one-fourth the strength at a distance of two inches and fifty times lower at three feet.

If you paid an electrical engineer to shield something for you, depending on the application, they would either use MuMetal or this type of mesh shielding. It’s not some new technology, so there’s no question of whether it works, because it does. Regardless, it would still be nice for them to publish third-party independent testing to reassure people of this.
First, you must have a proper meter. To check for magnetic field emissions, an AC Gaussmeter will work. Most AC gaussmeters will have an internal probe. Simply position the gaussmeter on the phone. Note carefully where the meter is positioned. Make a call and watch the readings. Notice the highest and lowest readings, and make a mental note of the "average" reading. Now, insert the magnetic shield, and repeat.
What the study showed: Self-reported cell phone use was not associated with an increased risk of glioma, meningioma, or non-central nervous system tumors. Although the original published findings reported an association with an increased risk of acoustic neuroma (14), this association disappeared after additional years of follow-up of the cohort (15).

"Possibly carcinogenic" was a phrase that may media outlets pulled out of the release, but it's a dangerous takeaway for consumers, out of context. "Possibly carcinogenic to humans", or group 2B, is a sub-classification or monograph, applied to agents by the IARC. Other agents (or items of everyday life) in Group 2B include pickled vegetables, lead and Potassium bromate — an oxidising additive common in flour. In all, there are 272 agents listed as possibly carcinogenic.
But the results of these two rat studies align with those of the biggest cell phone-radiation human study to date, INTERPHONE. The INTERPHONE study, published in 2011, was a coordinated effort by researchers at 16 institutions across 13 countries, and found that the heaviest mobile phone users were more likely to develop glioma—the same type of brain cancer the NTP study found in the male rats. “So there’s a concordance between the animal and human data,” Melnick says.
So of course now that we understand that the cases are not tested and just the material--it makes sense! We measured power density levels all around the case-the shielding material most likely isn't used "all over" because then the phone couldn't receive signal and wouldn't be able to engage in a call.  That's why we did not see even close to a 99% reduction when some cases were on the phone.  In fact, watch the video and you'll see some readings are more than 20% higher with a case on vs the naked phone.
Pong’s claims for its case have stood up to the scrutiny of Wired magazine and the Better Business Bureau (Advertising Self-Regulation Council 2012; Ganapati 2009). In tests conducted by Cetecom, a cell phone radiation certification lab, and observed by a reporter from Wired magazine, an iPhone 3G tested without a case had a maximum SAR of 1.18 W/kg when held at the ear. The same phone tested with a Pong case had a maximum SAR of 0.42 W/kg (Ganapati 2009).  
The electromagnetic spectrum is broken up into two parts based on whether small doses of that radiation can cause harm: ionizing radiation and non-ionizing radiation. Ionizing radiation—UV, x-rays, and gamma rays—has enough energy in one photon (quantized minimum packet of light) to remove electrons from atoms or break apart chemical bonds. It is because of this potential for cancer-causing DNA damage that you wear a lead vest when you get x-rays at the dentist and you are advised to wear sunblock when you go out in the sun. One can’t avoid natural (radon, cosmic rays when you are up in an airplane) and man made (diagnostic x-rays) sources of ionizing radiation completely, but it is reasonable advice to minimize exposure when possible.
That’s because cell phones emit electromagnetic fields (EMFs) or electromagnetic radiation, which has the potential to damage the cells in the body. In fact, the International Agency for Research on Cancer classifies EMFs from cell phones as possible carcinogens. EMFs can interfere with the body’s natural electrical system and disrupt sleep, immune system function, hormone production, and the healing process. Kevin Byrne, president of EMF Solutions, also points out the simultaneous increase in conditions such as chronic pain, depression, anxiety, chronic fatigue syndrome, and Alzheimer’s disease and the significant rise in EMF exposure.

“The near field plume is the one we’re most concerned with. This plume that’s generated within five or six inches of the center of a cell phone’s antenna is determined by the amount of power necessary to carry the signal to the base station,” he explains. “The more power there is, the farther the plume radiates the dangerous information-carrying radio waves.”
Rats were exposed to radiation with a frequency of 900 megahertz, typical of the cellphones in use when the study was conceived in the 90s, for about nine hours per day for two years, The New York Times reports. The lowest levels of radiation used in the study were equivalent to the maximum exposure a phone can cause and still receive federal regulatory approval; the highest levels to which the animals were exposed were four times that. 

I received mine yesterday in the mail. I have a Samsung Galaxy Note 3, and I cannot use this sock unless I take the case off. This is one thing I did not know when I was purchasing this material. I am trying it out as stated, however even when I use a rubber case or a very thin case with the sock its very tight to get off. I think the manufacturer needs to allow more room in these and or not state that it fits the larger phones at 6 inch. They should state that without the case it will fit. I am in the first day of walking around without a case, and just the sleeve. Its different, and if I drop my phone I'm in a world of hurt. I like the idea of this, but I was also surprised when the material really only feels like felt. It's not like the RF fabric that I have seen, and hopefully this is some kind of special blocking material as stated. I do like the idea, and I agree that cell phone radiation exist. Ill come back and give five stars if I really notice a difference, however if I drop my phone because I dont have a case I'm going to be posting less stars.
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:
“This means we’re on the beginning curve of an epidemic, with epidemic defined as a change in the occurrence of a disease that is so dramatic in its increase that it portends serious public health consequences,” says Dr. Carlo. “This is what’s not being told to the public. One of the things that I suggest to people who use a cell phone is to use an air tube headset. If you use a wired headset, the current moving through the wire of the headset attracts ambient informational carrying radio waves and thereby increases your exposure.”
There were no biological hypotheses tested in the study. It was therefore only a numbers game. Ignored were mechanisms of disease found in other studies of cell phone radiation effects, including genetic damage, blood-brain barrier leakage, and disrupted intercellular communication. The study did not discuss any research supporting the notion that cell phones could cause problems in users.
In the US, a small number of personal injury lawsuits have been filed by individuals against cellphone manufacturers (including Motorola,[28] NEC, Siemens, and Nokia) on the basis of allegations of causation of brain cancer and death. In US federal courts, expert testimony relating to science must be first evaluated by a judge, in a Daubert hearing, to be relevant and valid before it is admissible as evidence. In a 2002 case against Motorola, the plaintiffs alleged that the use of wireless handheld telephones could cause brain cancer and that the use of Motorola phones caused one plaintiff's cancer. The judge ruled that no sufficiently reliable and relevant scientific evidence in support of either general or specific causation was proffered by the plaintiffs, accepted a motion to exclude the testimony of the plaintiffs' experts, and denied a motion to exclude the testimony of the defendants' experts.[29]
The cell phone industry constantly guards its financial interests, but unfortunately, an unwitting public can be harmed in the process, says Dr. Carlo. “Industry-funded studies in many cases now produce industry-desired outcomes. By tampering with the integrity of scientists, scientific systems and public information steps over the lines of propriety that are appropriate for protecting business interests—especially when the casualty of the interference is public health and safety.”
A series of studies testing different scenarios (called simulations by the study authors) were carried out using incidence data from the Nordic countries to determine the likelihood of detecting various levels of risk as reported in studies of cell phone use and brain tumors between 1979 and 2008. The results were compatible with no increased risks from cell phones, as reported by most epidemiologic studies. The findings did suggest that the increase reported among the subset of heaviest regular users in the Interphone study could not be ruled out but was unlikely. The highly increased risks reported in the Swedish pooled analysis were strongly inconsistent with the observed glioma rates in the Nordic countries (24).