The device comes in a variety of forms ranging from the $39 Aries Shield ("a silicon based micro processor that ... decomposes oscillations of electromagnetic fields") to the $249 Aires Defender Utility (which "has two next generation 9 core silicon based micro processor (sic) that provide universal protection from electromagnetic smog of the broadband frequencies").
Anything you can do to keep the phone away from your head will help. (Even cell phone manufacturers warn consumers about this. See the previous post Cell Phone Manual Warnings for examples of warnings from Samsung, Apple and more.) If you hold the phone 2 inches away, the signal is about one-fourth the original strength. At four inches away, it’s about 1/16th as strong. Even better is a hands-free kit with a wireless air tube nearest the earpiece. (A regular wired headset can act as an antenna and make matters worse.)
Although this video was uploaded in 2012, don't even think it is not still perfectly valid and important at this time! It is even more valid considering all the clinical research proving the dangers of wireless radiation! This video provides a simple, yet profound lesson. The radio frequency radiation being transmitted from your wireless router or modem is extremely toxic and detrimental to your health. Notice how high the measurements are on the RF meter! Most of us are living and working in this type of RF radiation exposure every single day and night. The fix, or remediation is simple. Plug your modem or router into your computer using an Ethernet connection (hardwire), and "disable" the wireless function on your modem or router. This is very important for the health and safety of all those in your home or office. If you need to use the wireless function, then turn it on for a short time, do your task or watch your movie, then disable it once again. Never leave your wireless internet on all night as it will cause sleep disturbances which lead to even worse health issues. The fix is simple! Ethernet cord and disable the wireless function.
As I demonstrate in the video, you can see that with this router, I am exposed to about 100 times more Radio Frequency (RF) energy when I’m next to the router versus standing 20 feet away. This measurement video, like the others in our Video Library, give you an example of the varying levels of energy coming from our WiFi Routers.  If I was using the same meter on say, your WiFi, the measurements could vary widely. 

The present study was performed to investigate the effect of 2.45 GHz microwave radiation (2 h/day for 35 days) on reproductive pattern of male Wistar rats. Chronic exposure to these radiations produced formation of apoptotic cells in testis. In addition, a significant decrease in the levels of antioxidant enzymes glutathione and superoxide dismutase activities as well as an increase in catalase activity was observed in the exposed group. These results indicate that a low level exposure of microwave radiations exerts a negative impact on male reproductive system function.

The HPA also says that due to the mobile phone's adaptive power ability, a DECT cordless phone's radiation could actually exceed the radiation of a mobile phone. The HPA explains that while the DECT cordless phone's radiation has an average output power of 10 mW, it is actually in the form of 100 bursts per second of 250 mW, a strength comparable to some mobile phones.[8]

That may be true today. But some experts have grave concerns about the types of low-intensity radiation our wireless devices produce. “We have animal studies suggesting even low-level exposures to the kind of radio wave radiation associated with Wi-Fi could have a variety of negative health effects,” says Joel Moskowitz, director of the Center for Family and Community Health at the University of California, Berkeley. (Moskowitz has collected much of that research here.)

There was a negative correlation between the cell phone usage duration and the total sperm count (r = −0.064, p = 0.04). Similarly, there was also a negative correlation between the wireless internet usage duration and the total sperm count (r = −0.089, p = 0.019). Otherwise there were no significant correlations among the other four main question branches (cell phone usage time, cell phone carriage habits, wireless internet usage time. and internet connection type) and sperm parameters.
This is extremely important for a lot of reasons but will be crucial for any step to reducing radiation. Having a quality EMF meter will allow you to determine what kind of radiation devices in your home are emitted, as well as how much. This will also be crucial in understanding how different changes are improving this I would highly recommend either the TriField TF2 (read my review), or Meterk (read my review) if you need a lower cost EMF meter.
The environmental exposure to RF radiation in some schools is higher than reported levels for non-thermal biological effects. In order to reduce children’s exposure to RF radiation, schools should prefer wired network connections, allow laptop, tablets, and mobile phone usage only in flight mode and deactivate Wi-Fi access points when internet is not needed for learning purposes.
The present study was carried out to investigate the potential combined influence of maternal restraint stress and 2.45 GHz WiFi signal exposure on postnatal development and behavior in the offspring of exposed rats. 24 pregnant albino Wistar rats were randomly assigned to four groups: Control, WiFi-exposed, restrained and both WiFi-exposed and restrained groups. Each of WiFi exposure and restraint occurred 2 h/day along gestation till parturition. The pups were evaluated for physical development and neuromotor maturation. Moreover, elevated plus maze test, open field activity and stationary beam test were also determined on postnatal days 28, 30 and 31, respectively. After behavioral tests, the rats were anesthetized and their brains were removed for biochemical analysis. Our main findings showed no detrimental effects on gestation progress and outcomes at delivery in all groups. Subsequently, WiFi and restraint, per se and mainly in concert altered physical development of pups with slight differences between genders. Behaviorally, the gestational WiFi irradiation, restraint and especially the associated treatment affected the neuromotor maturation mainly in male progeny. At adult age, we noticed anxiety, motor deficit and exploratory behavior impairment in male offspring co-exposed to WiFi radiation and restraint, and in female progeny subjected to three treatments. The biochemical investigation showed that, all three treatments produced global oxidative stress in brain of both sexes. As for serum biochemistry, phosphorus, magnesium, glucose, triglycerides and calcium levels were disrupted. Taken together, prenatal WiFi radiation and restraint, alone and combined, provoked several behavioral and biochemical impairments at both juvenile and adult age of the offspring.
Nevertheless, a group of scientists got together in the mid-2000s, calling themselves the BioInitiative Working Group. This group, which largely consisted of wireless radiation researchers, has written a harsh reply as feedback to the reports claiming that posed no health risks.  The reply lists a wide range of health effects scientists at the European Commission have unfortunately either ignored or dismissed.