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.
Although recall bias is minimized in studies such as COSMOS that link participants to their cell phone records, such studies face other problems. For example, it is impossible to know who is using the listed cell phone or whether that individual also places calls using other cell phones. To a lesser extent, it is not clear whether multiple users of a single phone, for example family members who may share a device, will be represented on a single phone company account. Additionally, for many long-term cohort studies, participation tends to decline over time.
EWG urges the FCC to include third party-produced cases and accessories in its cell phone testing policies to ensure that they do not compromise cell phone function and do not prevent a cell phone from complying with the Commission’s exposure limits. Manufacturers should publish the radiation data for a given phone when used directly next to the body and when used with the cases most commonly sold for a specific model.
Since speaking with Samet, further details came out from a large study that beamed high levels of phone radiation at rats and mice. While there remain quirks in the findings, the latest evidence still doesn’t find a link between phone radiation and cancer. In response, the FDA said, “Taken together, all of this research ... [has] given us the confidence that the current safety limits for cell phone radiation remain acceptable for protecting the public health.”
We tested a variety of cellphone cases and garment shielding products including the Safe Sleeve, Defender Shield, RF Safe  cellphone “flip” cases, and the Pong cellphone case which does not have a cover over of the face of the phone. We also tested the Belly Armor blanket, nursing cover and boxers as well as an anti-radiation tank top sold by OurSure on Amazon.

When you make a phone call, just flip the shielded front cover down when you put the phone against your head. It’s that simple. By keeping the shielded front cover closed while against any part of your body, a barrier is created to protect from a broad spectrum of potentially harmful cell phone radiation emissions, yet won’t affect signal quality. You can use your cell phone with a higher sense of safety by simply keeping the shielded flip cover between your body and radiation-emitting source.
In one type of study, called a case–control study, cell phone use is compared between people with these types of tumors and people without them. In another type of study, called a cohort study, a large group of people who do not have cancer at study entry is followed over time and the rate of these tumors in people who did and didn’t use cell phones is compared. Cancer incidence data can also be analyzed over time to see if the rates of brain tumors changed in large populations during the time that cell phone use increased dramatically. These studies have not shown clear evidence of a relationship between cell phone use and cancer. However, researchers have reported some statistically significant associations for certain subgroups of people.