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.
Unfortunately, regulatory boards do not require third-party phone accessory manufacturers to consider how their product will work in tandem with the smartphone. Neither do governments require smartphone manufacturers to conduct extensive research on whether their SAR will still meet the FCC’s allowable radiation exposure limits when their devices are using a phone case or other 3rd party accessories.
We couldn't find one legit EMF expert online or anywhere else that would recommend a radiation blocking case or anti-radiation case. Not the Environmental Health Trust or Magda Havas, or Joel Moskowitz, in fact his site, safeEMR cautions against scams and claims for radiation protection.  So if a so-called "EMF expert" is recommending any kind of anti-radiation case, they probably aren't that much of an expert. 
Stereo Hands-Free Headset with a gold plated 3.5mm, 3 band plug. Sporty lightweight design, this headset provides clear stereo sound quality comfortably to your ears. The convenient microphone allows you to make and receive calls at the touch of a button. Compatible with all universal 3.5mm headphone jacks. Can be used with Ferrite Snap Bead to further reduce RF exposure.
But, dear reader, don’t think we’ve reached a “case closed” moment: Unfortunately, even the best evidence on cellphones and brain tumors is far from ideal. Remember, these cohort studies are still observational research — not experimental studies like RCTs. That means they can’t tell us about causation, and there are still many ways they could be biased.
But, dear reader, don’t think we’ve reached a “case closed” moment: Unfortunately, even the best evidence on cellphones and brain tumors is far from ideal. Remember, these cohort studies are still observational research — not experimental studies like RCTs. That means they can’t tell us about causation, and there are still many ways they could be biased.
Thus far, the data from studies in children with cancer do not support this theory. The first published analysis came from a large case–control study called CEFALO, which was conducted in Denmark, Sweden, Norway, and Switzerland. The study included children who were diagnosed with brain tumors between 2004 and 2008, when their ages ranged from 7 to 19 years. Researchers did not find an association between cell phone use and brain tumor risk either by time since initiation of use, amount of use, or by the location of the tumor (21).

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]
Hi August and Tech Wellness Team. We at SafeSleeve salute you for your effort to educate and provide solutions for the hidden dangers of EMF radiation exposure from wireless electronics. Like you, we’ve worked extremely hard to provide a practical solution for EMF exposure and, as verified by our independent lab testing, we believe we’ve found an extremely effective and practical solution. While I cannot speak for the other devices you tested here, there are some key points about our SafeSleeve technology that we wanted to make sure you took into consideration:
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).  
Some products ( for example) are tested using a piece of shielding material in a laboratory test jig. These tests legitimately show the amount of radiation which penetrates the shield, but results will be very different when compared to putting a small amount of the same shield on a large transmitter like a cellphone. Remember, the entire phone radiates. Placing a small amount of shielding, even if it is an effective shielding material, only shields that small area at best. Think about this analogy: no light will penetrate a penny as it is a very effective light shield, but it is silly to think that holding a penny up to the sun will put you in darkness.
The effect of mobile phone radiation on human health is a subject of interest and study worldwide, as a result of the enormous increase in mobile phone usage throughout the world. As of 2015, there were 7.4 billion subscriptions worldwide, though the actual number of users is lower as many users own more than one mobile phone.[1] Mobile phones use electromagnetic radiation in the microwave range (450–3800 MHz and 24-80GHz in 5G mobile). Other digital wireless systems, such as data communication networks, produce similar radiation.
The use of "hands-free" was not recommended by the British Consumers' Association in a statement in November 2000, as they believed that exposure was increased.[41] However, measurements for the (then) UK Department of Trade and Industry[42] and others for the French Agence française de sécurité sanitaire environnementale [fr][43] showed substantial reductions. In 2005, Professor Lawrie Challis and others said clipping a ferrite bead onto hands-free kits stops the radio waves travelling up the wire and into the head.[44]
SafeSleeve's report is right up front about showing that they do not test or certify the Safe Sleeve case, rather they are simply testing the material they put into the case in a completely artificial environment, in a laboratory setting, using a signal generator and a power amplifier. Safe Sleeve includes photos showing how the measurements are taken. But that may not be how anyone will ever use their phone.
The World Health Organisation (WHO) released a fact sheet about these issues, shortly after the IARC re-classification, entitled "Electromagnetic fields and public health: mobile phones". The fact sheet points to the findings of the IARC and describes some of the known short-term and long-term effects of phone use, but ultimately, it lands on the side of where the most conclusive evidence exists:
In 2011, the American Cancer Society (ACS) stated that the IARC classification means that there could be some cancer risk associated with radiofrequency radiation, but the evidence is not strong enough to be considered causal and needs to be investigated further. Individuals who are concerned about radiofrequency radiation exposure can limit their exposure, including using an ear piece and limiting cell phone use, particularly among children.

There are few if any references to actual studies in published, peer-reviewed journals that support the claim that Aires, or any other, cell phone shield actually works. The "Researches" page contains a superficially impressive list of sciencey-sounding titles and findings supposedly demonstrating the importance of using cell phone shields, all of them in Russia for some reason.

The World Health Organization (WHO) says the intensity of radio frequency (RF) radiation from cell phones decreases exponentially the further the device is held away from the body. Therefore your safest bet it keep your cell phone as far away from your ear and body as possible at all times. Don’t carry it in your pocket, tucked into a bra strap, and definitely don’t sleep with it next to your head.
Wherever you come out on the cellphone and cancer question, one thing is clear: How we live with cellphones, along with our exposure to the radiation they emit, has changed dramatically over the past several decades. That has policy implications; it’s something regulators, researchers, and cellphone companies need to pay attention to. In that context, a few things should happen:

Jump up ^ "Téléphones mobiles : santé et sécurité" (in French). Le ministère de la santé, de la jeunesse et des sports. 2 January 2008. Retrieved 19 January 2008. Lay article in (in English) making comment at Gitlin, Jonathan M. (3 January 2008). "France: Beware excessive cell phone use?: despite lack of data". Ars Technica. Retrieved 19 January 2008.
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.
But the 5G signals are weaker at traveling long distances, and weaker signals mean we need more antennas to amplify, or strengthen, the 5G network. According to the New York Times, “Instead of relying on large towers placed far apart, the new signals will come from smaller equipment placed an average of 500 feet apart in neighborhoods and business districts.” They’ll also emit a different kind of higher-frequency radio waves, known as millimeter waves.

The following charts list SAR levels for the Apple iPhone, Samsung Galaxy S, as well as 20 of the highest SAR level cellphones and 20 of the lowest SAR level cellphones. The list provides the maximum possible SAR level from the phone (many phones have differing SAR levels depending on where and how the phone is used). If your phone is not on either list, you can find the SAR level for your specific phone by checking the online FCC database.

We really do not recommend any kind of chip, guard, anti-radiation "filters" or incomplete shielding case because honestly, how could they NOT provide a false sense of security? Folks could believe these products make them “invincible” against radiation so they are comfortable holding the case right up to their heads-and the radiation seeping from the back and the side of the phone case is in very close proximity to their precious brains. Oh no!
Features an outstanding 38-pound puncture resistance. The multiple layer construction provides full protection against ESD, EMI/RFI and tribocharging. Because its moisture barrier performance exceeds foil laminates for low Moisture Vapor Transmission Rate (MVTR), particularly after flexing, whatever you place in the bag and seal properly is going to stay dry also! Does not provide magnetic shielding.
Regular battery-powered watches (and all other battery-powered tech, for that matter) also produce some level of EMFs, but that level is far lower than the amount emitted by tech devices that are plugged in, or that receive and transmit information wirelessly. The same rule applies however; if you can turn it off and keep it away from your body, then do so whenever possible.
The owner of a damaged case are always encouraged send it in for a replacement and when available a 2nd generation final production case is always sent. As demand increases for a particular color and model — silicon cases are made with RF Safe’s peel-n-shield embedded inside the flip cover. The 2nd Gen cover also includes room for a credit card but this is discouraged because excessive conductive RFID material that pushes the shielding at an angle from a phones surface can compromise shielding effectiveness.

In subsequent analyses of Interphone data, investigators addressed issues of risk according to specific location of the tumor and estimated exposures. One analysis of data from seven of the countries in the Interphone study found no relationship between brain tumor location and regions of the brain that were exposed to the highest level of radiofrequency radiation from cell phones (9). However, another study, using data from five of the countries, reported suggestions of an increased risk of glioma and, to a lesser extent, of meningioma developing in areas of the brain experiencing the highest exposure (10).