But there’s a huge public health crisis looming from one particular threat: EMR from cellular phones—both the radiation from the handsets and from the tower-based antennas carrying the signals—which studies have linked to development of brain tumors, genetic damage, and other exposure-related conditions.1-9 Yet the government and a well-funded cell phone industry media machine continue to mislead the unwary public about the dangers of a product used by billions of people. Most recently, a Danish epidemiological study announced to great fanfare the inaccurate conclusion that cell phone use is completely safe.10
All cell phones emit Electromagnetic Radiation (EMR). Most people are aware of Radio Frequency (RF) (also known as Microwave) signals that connect your cell phone to a cell tower, a WiFi router and Bluetooth devices. These cell phone signals are always on. But did you know that cell phones also emit Extremely Low Frequency (ELF) radiation produced by the cell phone’s internal components?
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.
The first one is easy, cellular frequencies vary between 450–2000MHz, but 800 or 900 MHz is the most common. The power emitted by a cell phone varies over the course of the call (higher when making initial contact, which lasts a few seconds). It can go up to 2 Watts at the start of a call, and can go down to .02 Watts during optimal operation [2]. Of course, most people barely use cell phones for calls, but I am using this example as a worst case scenario, because the phone is not right by your head when you are browsing Tinder.

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.

Affirming research conducted back in the 1970s that brought to light some of the dangers associated with EMFs, scientists from the Environmental Protection Agency (EPA) more recently warned that ELF radiation alters calcium ion activity in cells, which regulates energy production, membrane function and integrity, and both central and peripheral nervous system health.
Cables can act as an antenna, especially if they pass close to a strong source of radiofrequency radiation. One study has suggested that if the cable of a hands free mic passes near the phone's antenna, it can pick up some radiation and transmit it to your ear. Our ferrite snap bead is designed to reduce RF radiation in the cable. Made in 2 halves, you simply press it around the hands free wire at any convenient location near the earpiece end. Couldn't be simpler. It is small and lightweight enough to be almost unnoticable, yet powerful enough (50 ohm impedence minimum) to control nasty radiation. These are brand new, top quality and will accommodate wires up to 5 mm (3/16 inch) in diameter. About 1 inch long, grey color. If you are concerned about radiation from your hands free ear mic, this is the answer. Useful from 200-1000 MHz.
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 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.”
The Working Group indicated that, although the human studies were susceptible to bias, the findings could not be dismissed as reflecting bias alone, and that a causal interpretation could not be excluded. The Working Group noted that any interpretation of the evidence should also consider that the observed associations could reflect chance, bias, or confounding rather than an underlying causal effect. In addition, the Working Group stated that the investigation of risk of cancer of the brain associated with cell phone use poses complex methodologic challenges in the conduct of the research and in the analysis and interpretation of findings.
There’s a broad range of radiation types, and lots of harmless things emit radiation — like bananas, Brazil nuts, and granite countertops, according to Cincinnati Children’s Hospital. The type of radiation that comes out of our cellphones isn’t the same radiation that’s released by nuclear fallout or X-rays. Cellphone radiation, also known as radiofrequency radiation, is much weaker — so it can’t cause the same kind of cell damage that can lead to cancer.

The only consistently recognized biological effect of radiofrequency radiation in humans is heating. The ability of microwave ovens to heat food is one example of this effect of radiofrequency radiation. Radiofrequency exposure from cell phone use does cause heating to the area of the body where a cell phone or other device is held (e.g., the ear and head). However, it is not sufficient to measurably increase body temperature. There are no other clearly established effects on the human body from radiofrequency radiation.