An analysis of an "eagerly anticipated" study using rats and mice by the National Toxicology Program indicates that due such issues as the inconsistent appearances of "signals for harm" within and across species and the increased chances of false positives due to the multiplicity of tests, the positive results seen are more likely due to random chance. The full results of the study were released in February 2018.[10]
Leibovich was very careful to point out in our interview that Cellsafe is not claiming that the radiation absorbed by the body during phone use leads to health issues like brain tumours, male infertility or damage to unborn babies. But the Cellsafe website strongly suggests these links. Its homepage (image below) leads with the phrase "You should be concerned!" in an eye-catching red, and there is as much screen real estate on the site dedicated to information about the dangers of radiation, as there is for descriptions of the Cellsafe products. This information refers to "high levels of RF radiation" in several places, but it doesn't say whether this describes radiation from phone use.
During the years 1996-1999, due to the sharp increase in mobile phone use, several expert committees convened worldwide to discuss the question whether the radiowave radiation that is emitted from the mobile phone is harmful to health. Their conclusion was that existing scientific knowledge is insufficient to determine the existence or absence of harm to health.

Can cellphone radiation cause cancer in humans? There’s no scientific consensus on this issue, but there is “some evidence” that exposure to radiation equivalent to that emanating from 1990s-era cellphones is associated with brain tumors in male rats, according to results of a US National Toxicology Program (NTP) study released last week (November 1). 
In June, at a meeting of scientific counselors to the toxicology agency, Donald Stump, one of the members, worried that the study “will be vulnerable to criticism that it was conducted using outdated technology.” The challenge, he added, is how to move forward with experiments that are large enough to be significant yet nimble enough to keep pace with the rapidly evolving devices.
But, like the human studies, one can pick apart the NTP studies too. For one thing, the animals experienced cell phone radiation that was different from what humans live with. As Bucher said in a statement, “In our studies, rats and mice received radio frequency radiation across their whole bodies. By contrast, people are mostly exposed in specific local tissues close to where they hold the phone. In addition, the exposure levels and durations in our studies were greater than what people experience.”
SafeSleeve was founded in California by two Engineering graduates (University of Cal Poly San Luis Obispo) Cary and Alaey, with a desire to make a difference. They wanted to develop a product to help simplify, protect, and enhance the lives of their increasingly busy, tech dependent peers, family and friends. This is apparent in the highly efficient and useful, yet stylish designs and branding of SafeSleeve products. 
The BlocSock is a small, 3”x5½”, lightweight case that's only designed for cell phones, not tablets or laptops. One side is a normal fabric to ensure reception. The other side has a rectangular, metallic mesh to shield RF radiation. It's recommended that you keep the side with the shielding material between the phone and your body. When making or receiving calls, keep the shielding between your head and the phone. It can also be moved into a smaller “kangaroo style” pouch during calls. It's effective, and tests show that it reduces RF exposure 96%. For more information, check out the SAR research test or watch this video.
The perfect way to shield your ears. Comfortable enough to sleep in, and stylish enough to wear in public. High shielding performance silver stretch fabric gives excellent radiofrequency and microwave shielding. Made of double thickness 2" wide 71% polyamide + 29% elastomer fiber. Ideal for cellphone shielding or any other activity when you need to shield your ears and forehead. Thin enough to fit under a hat or helmet. Durable and unwrinkleable, washable too (no bleach). Silver provides anti-bacterial properties and suppresses odor. Folds small for easy transport. Pretty Silver color.
So, what types of RF are these cases intended to block? If they block the frequency being used by the phone than if the blocking is complete the phone won’t work. If it’s partial than, as noted by the FCC and related in the article, the phone may attempt to compensate for the weakened signal by increasing it’s signal strength, thereby emitting higher levels of radiation itself, and reducing battery life in the process.
As far as which of those match your device, that really depends on your carrier. AT&T, Verizon, Sprint, and T-Mobile all have different frequencies. To further complicate things, in one geographic region of the country they may use one frequency, while another is used elsewhere. It all depends on which FCC licenses they have the rights to in each region.
Yes, cell phones emit Electromagnetic Fields (EMF) and direct exposure to these emissions can be a health risk. There are two types of EMF radiation emitted from cell phones: Extremely Low Frequency (ELF) radiation and Radio Frequency (RF) radiation (which includes cellular signals, WiFi and Bluetooth). More and more, particularly in recent years, scientific studies have confirmed that these EMF exposure can adversely modify the biological operations of the body. In more serious cases, exposure to EMFs can lead to tumors, reduce sperm count and other serious health concerns.
This 2009 meta-analysis, published in the Journal of Clinical Oncology, looked at 23 case-control studies of the risk of both malignant and benign tumors from mobile phone use. When the authors included all 23, they found no increased risk of tumors. When they crunched certain subsets of the data — like looking only at studies that were blinded, or people who used cellphones for 10 or more years — they did find increases in tumor risks. Confusingly, when they divided up the analysis by tumor type, they found no increase in risk for glioma and acoustic neuroma, and a decrease in risk of meningioma.
They get upset to learn that the video game console requires them to use their hands to play it, and one exclaims “That’s a baby’s game!” I’m thinking “Whoa, I never want to be that dependent on technology that I don’t want to use my hands. I’ve heard many people say “my cell phone is my right arm, or I can’t live without my cell phone. How many of you recall the movie “Johnny Mnemonic(1995)” It was about the effect technology was having on the human body. Nerve Attenuation Syndrome (NAS)
Like we talked about in the last section, SAR limits that are reported are the maximum possible radiation emitted from the device, however, this level is not what is common with the regular use of the device. Just because one cell phone has a higher maximum SAR level, doesn’t mean that the radiation level of normal use isn’t higher or lower than another device with a different maximum SAR level.
Yes, the information transferred between the base unit (the phone’s stationary unit) and the wireless phone’s mobile unit is transferred as radiowave radiation. Therefore, the “precautionary principle” should also be adopted regarding wireless phones. In addition to the guidelines regarding mobile phones, the Ministry of Health recommends regarding wireless phones:
Researchers have carried out several types of epidemiologic studies in humans to investigate the possibility of a relationship between cell phone use and the risk of malignant (cancerous) brain tumors, such as gliomas, as well as benign (noncancerous) tumors, such as acoustic neuroma (tumors in the cells of the nerve responsible for hearing that are also known as vestibular schwannomas), meningiomas (usually benign tumors in the membranes that cover and protect the brain and spinal cord), and parotid gland tumors (tumors in the salivary glands) (3).