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.
The next day, telecommunications stocks took a big hit on Wall Street and the media had a field day. The industry trade association at the time, the Telecommunications Industry Association (TIA), went into crisis mode, claiming thousands of studies proved cell phones were safe and what Reynard and his attorney said was bunk. TIA reassured the public that the government had approved cell phones, so that meant they were safe. The media demanded to see the studies, but, says Dr. Carlo, “The industry had lied. The only studies in existence then were on microwave ovens. At that time, 15 million people were using cell phones, a product that had never been tested for safety.”
Manufacturers conduct government-required certification tests using a bare phone, set to transmit at maximum power, with no accessories. The recorded maximum SAR is reported to the FCC and listed in the phone’s manual. A phone tested with accessories under the same conditions can produce a higher SAR because the materials surrounding the antenna can affect the amount of radiation that reaches and is absorbed by the user’s body. A case can influence both the overall amount of emitted radiation and how it is directed.
A recent small study in people has shown that cell phones may also have some other effects on the brain, although it’s not clear if they’re harmful. The study found that when people had an active cell phone held up to their ear for 50 minutes, brain tissues on the same side of the head as the phone used more glucose than did tissues on the other side of the brain. Glucose is a sugar that normally serves as the brain’s fuel. Glucose use goes up in certain parts of the brain when it is in use, such as when we are thinking, speaking, or moving. The possible health effect, if any, from the increase in glucose use from cell phone energy is unknown.
That’s why randomized controlled trials (RCTs) often yield fairly clear answers about the effectiveness of treatments compared to other study designs. (Fun fact: Scottish doctor James Lind, a clinical trial pioneer, figured out that citrus fruits seemed to have an effect on scurvy using one of the earliest RCTs.) RCTs can also be used to study whether something, like cellphone radiation, can cause disease.
INTEGRITY: Many manufactures claim near 100% EMF protection, referring to the radiation blocking material, NOT the protection you receive on a call. If you covered your whole phone with EMF blocking material, then you'd have no signal. Our EMF blocking material is used on the front cover only, providing you real EMF protection with no sacrifice in reception.

If you want to measure the EMF radiation from your own phone, and know if EMF protection products are working, you should get a quality EMF meter. I highly recommend the new TriField TF2 (read my review) as it’s simple to use, lasts forever, is extremely accurate, and measures all three types of EMF radiation. If you’re looking for a low-cost EMF meter I really like the Meterk (read my review).

In March, however, a peer-review panel of 11 experts from industry and academia voted to advise the agency that it should raise the confidence level from “equivocal evidence” to “some evidence” of a link between cellphone radiation and brain tumors in male rats. (The female rats did not show evidence of a link between the radiation and such tumors.) Two panel members, Lydia Andrews-Jones of Allergan and Susan Felter of Procter & Gamble, proposed the risk upgrade.
If you want to use your phone for talking, then the idea is that you keep it flipped over the front of the screen – that way you’re blocking radiation on both the front and back. The speaker still works with the cover on, because there’s a small hole for that. The inevitable drawback of this is that you have to flip the cover open in order to access your keypad.

Pong Research also makes cases for the iPad and its technology is arguably better suited for that. Why? Because serving as a stand to prop up your iPad or tablet, it means you don’t really need to hold it. That’s an ideal setup because higher amounts of radiation are going out the back, versus the front of the screen which you are touching with your fingers and palms.
I debated whether to give it 3 or 4 stars: on features, speed of delivery, and quality of construction, it definitely deserves 4 stars. If I can measure and verify the emf reduction, then I will change the rating to 5 stars. Since the whole point of using it is to block excess em radiation, I can't really give it 5 stars without more proof that it really does so.
Current regulatory standards (SAR Test) only protect us from thermal or heating risks; yet, many hundreds of laboratory studies have found that low-intensity, non-thermal exposure to cell phone radiation can promote carcinogenic mechanisms. Moreover, research on humans has found that 25 years of mobile phone use is associated with a three-fold risk of brain cancer.  –Joel M. Moskowitz, Ph.D. School of Public Health. University of California, Berkeley
They determined there is “clear evidence” that male rats exposed to high levels of radio frequency radiation — typical of 2G and 3G networks when the study was designed — developed heart schwannomas. There was also “some evidence” of brain and adrenal gland tumors, again in the male rats, but the exposed female rats, and male and female mice, did not have consistent patterns of disease.
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.
(Some common flaws in these studies: The summaries of the evidence weren’t comprehensive, the researchers often didn’t look at the quality of the studies they found, and they failed to do other simple things that would limit bias from creeping in. They also relied on case-control studies, a poor method to determine causality — more on that soon.) So we didn’t include these eight reviews in our analysis.
In fact, nobody can really explain how exactly cellphone radiation could cause cancer, says Christopher Labos, a cardiologist and biostatistician at McGill University. “You don’t necessarily have to understand how something works to prove that it’s dangerous, but it would certainly make the case more compelling,” says Labos, who wrote a detailed analysis for Science-Based Medicine about the recent government cellphone radiation study.
A full featured desktop or wall mount corded telephone (no microwaves) combined with a special ultra low EMF headset. You get all the benefits of a normal telephone without putting yourself close to the strong magnetic fields associated with the handset, speakerphone, or phone base. The special headset cord is about 3 feet long and uses a plastic tube to carry the sound to your ear. Absolutely no electronics, wires or magnets are near your ear. Cord provides distance from telephone base and traditional handset, convenient mobility, and can be extended up to 15 feet with option extension cord, sold separately (see below). Tested and approved by Less EMF Inc., dramatic field reduction when the headset is used. Although pictured as white, our current stock is a black phone.

Since 2001, the FCC has allowed manufacturers to test phones at a distance of up to one inch from the body to account for the use of a holster. In a 2012 report, however, the Government Accountability Office, the Congressional watchdog agency, noted that many cell phone owners actually keep and use their phones right next to the body, so these outdated testing policies could result in radiofrequency (RF) radiation exposure greater than the FCC’s legal limit (GAO 2012). The GAO report concluded:

The authors of these studies noted that the results were preliminary and that possible health outcomes from changes in glucose metabolism in humans were unknown. Such inconsistent findings are not uncommon in experimental studies of the biological effects of radiofrequency electromagnetic radiation in people (4). Some factors that can contribute to inconsistencies across such studies include assumptions used to estimate doses, failure to consider temperature effects, and lack of blinding of investigators to exposure status.