The outside is made of a synthetic polyurethane that feels just like leather, although genuine leather will be available soon. The inside is made of a microfiber that won’t scratch the phone. The materials are also designed to protect your phone, should you drop it. Most importantly, an integrated FCC-certified lab tested radiation-shielding foil not only deflects and absorbs RF, ELF and Thermal radiation to greatly reduce your exposure, but it also blocks RFID signals, so that hackers cannot steal your credit card information by scanning it from afar. And no, the case will not affect phone or battery performance.
Wearable tech such as the Apple Watch might as well be called a wearable EMF device. These watches are even worse than mobile phones in that they remain in constant, direct contact with your skin. New York Times columnist Nick Bilton covered this issue in March 2015, noting that constant, low-level radiation from such devices can trigger the formation of cancerous tumors, blood abnormalities, and more.
“Epidemiological studies are targets for fixing the outcome because they’re observational in nature instead of experimental,” Dr. Carlo explains. “It’s possible to design studies with pre-determined outcomesthat still fall within the range of acceptable science. Thus, even highly flawed epidemiological studies can be published in peer-reviewed journals because they’re judged against a pragmatic set of standards that assume the highest integrity among the investigators.”
In this frequency range, the interaction between matter and light is via the electric field component of light (totally different from how ionizing radiation messes you up). In particular, an oscillating electric field causes polar molecules to rotate or attempt to rotate, and the lag between the applied field and the response of the molecules manifests as dissipation—i.e. heating . This is the same dielectric heating which is the operating principle behind microwave ovens (which operate at 2450 MHz  similar to wifi). So if cell phones were to cause damage to tissue, the mechanism would be the same as what happens in a microwave oven—boiling the water in your head/body.
I noticed the Blocsock hardly added any bulk to my phone, and fit comfortably in my pocket. I have a Rocketfish RF-MTVT2SP protective gel case and thankfully the phone fits the Blocsock without having to take off this case. The Blocsock is very easy to use, and is quick and easy to take out and answer the phone. Again, if you get one, make sure the size you order is right and not too tight or loose. The pouch on the Blocsock is handy when using the phone to call people so the phone can be placed in the pouch between the Blocsock and me, protecting my head from radiation while still enabling people to clearly hear me and vice versa.
Radiofrequency radiation is a form of electromagnetic radiation. Electromagnetic radiation can be categorized into two types: ionizing (e.g., x-rays, radon, and cosmic rays) and non-ionizing (e.g., radiofrequency and extremely low frequency, or power frequency). Electromagnetic radiation is defined according to its wavelength and frequency, which is the number of cycles of a wave that pass a reference point per second. Electromagnetic frequencies are described in units called hertz (Hz).