"Someone claiming they need to reduce [the safe SAR level of 2 W/kg] by 90-percent — they just have no evidence to make that claim, and they are actually playing on the fact that people will be concerned enough about the possible cancer risk, although they don't understand that there's no sufficient data yet to make a statement about an actual cancer risk," said Professor Olver.

It’s easy to call any case a product designed to block smartphone radiation.  What you need to look for is credible, quantifiable claims that highlight a case’s ability to reduce your exposure to the harmful radiation. Look for relevant  certifications from credible organizations (such as FCC accredited laboratories) that will vouch for product claims, and read product reviews online.

The three most common brain tumor types — and the ones most cellphone and human health studies focused on — are gliomas (malignant tumors of the brain and spinal cord), meningiomas (mostly noncancerous tumors of the membranes surrounding the brain and spinal cord, though a small percentage are cancerous), and acoustic neuromas (noncancerous tumors on the main nerve that leads from the inner ear to the brain). Note that of these, gliomas are the main concern — they generally have more severe outcomes than meningiomas and acoustic neuromas.
That’s because cell phones emit electromagnetic fields (EMFs) or electromagnetic radiation, which has the potential to damage the cells in the body. In fact, the International Agency for Research on Cancer classifies EMFs from cell phones as possible carcinogens. EMFs can interfere with the body’s natural electrical system and disrupt sleep, immune system function, hormone production, and the healing process. Kevin Byrne, president of EMF Solutions, also points out the simultaneous increase in conditions such as chronic pain, depression, anxiety, chronic fatigue syndrome, and Alzheimer’s disease and the significant rise in EMF exposure.
A recent large study by the US National Toxicology Program (NTP) exposed large groups of lab rats and mice to RF energy over their entire bodies for about 9 hours a day, starting before birth and continuing for up to 2 years (which is the equivalent of about 70 years for humans, according to NTP scientists). The study found an increased risk of tumors called malignant schwannomas of the heart in male rats exposed to RF radiation, as well as possible increased risks of certain types of tumors in the brain and adrenal glands. But some aspects of this study make it hard to know just how well these results might be applied to cell phone use in people. For example, there was no clear increased risk among female rats or among male or female mice in the study. The doses of RF radiation in the study were also generally higher than those used in cell phones (ranging from 1.5 W/kg to 6 W/kg in rats, and 2.5 W/kg to 10 W/kg in mice), the animals’ entire bodies were exposed, and the amount of time they were exposed was longer than most people typically spend on the phone each day. The male rats in the study exposed to RF waves also lived longer, on average, than the rats who were not exposed, for unclear reasons. Because of this, the NTP has noted that the study results cannot be directly applied to humans. Still, the results add to the evidence that cell phone signals might potentially impact human health.
Limit your (and your children’s) cell phone use. This is one of the most obvious ways to limit your exposure to RF waves from cell phones. You may want to use your cell phone only for shorter conversations, or use it only when a conventional phone is not available. Parents who are concerned about their children’s exposure can limit how much time they spend on the phone.
For example, cellphone manufacturers currently test these devices for compliance with FCC standards by placing them against the head, and near the torso with some separation. Just check out Apple’s iPhone manual: The company tests the specific absorption rate at a 5mm separation from the body. But if you wear your device in your pocket, you’re probably not going to have that 5mm separation, meaning you may be exposed to more radiation — perhaps enough to exceed current standards.

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.

W. Kim Johnson, a retired physicist and past president of the New Mexico Academy of Science, reviewed the Aires web site for Discovery News and described the material as gibberish, saying that the authors "of the technical description of the ‘Aires' device reads like a random selection of technical terminology. The working description for this device is made up of jargon that, in the end, really says nothing."
But scientists disagree on how real—or how serious—these risks really are, and studies have not established any definitive links between health problems and radiofrequency (RF) energy, the type of radiation emitted by cell phones. “This document is intended to provide guidance for people who want to reduce their own and their families’ exposure to RF energy from cell phones,” the guidelines state, “despite this uncertainty.”
The energy of electromagnetic radiation is determined by its frequency; ionizing radiation is high frequency, and therefore high energy, whereas non-ionizing radiation is low frequency, and therefore low energy. The NCI fact sheet Electromagnetic Fields and Cancer lists sources of radiofrequency radiation. More information about ionizing radiation can be found on the Radiation page.