I debated whether to give it 3 or 4 stars: on features, speed of delivery, and quality of construction, it definitely deserves 4 stars. If I can measure and verify the emf reduction, then I will change the rating to 5 stars. Since the whole point of using it is to block excess em radiation, I can't really give it 5 stars without more proof that it really does so.
Since 2001, the FCC has allowed manufacturers to test phones at a distance of up to one inch from the body to account for the use of a holster. In a 2012 report, however, the Government Accountability Office, the Congressional watchdog agency, noted that many cell phone owners actually keep and use their phones right next to the body, so these outdated testing policies could result in radiofrequency (RF) radiation exposure greater than the FCC’s legal limit (GAO 2012). The GAO report concluded:
Dr. Carlo, wrote a  Medical Alert ten years ago. He cautioned people with EMF sensitivity against relying upon widely-available EMR Protection Products to prevent the effects of EMF exposure. He noted that EMF sensitive individuals were reporting the opposite effect: people found their symptoms and/or sensitivity worsened. Specifically, severe “symptom relapses.” Dr. Carlo noted:

Cell phones emit low levels of radio frequency energy (i.e., radio frequency radiation) in the microwave range while being used. It is well known that high levels of RF can produce biological damage through heating effects (this is how your microwave oven is able to cook food). However, it is not known to what extent or through what mechanism, lower levels of RF might cause adverse health effects as well. Several research studies have shown that the radio frequency radiation from wireless phone antennae “appears to cause genetic damage in human blood,” while another case study uncovered a “statistically significant increase” in neuro-epithelial brain tumors among cell phone users. Other research has shown little or no adverse effects. ABC’s 20/20 News (May 26, 2000) took the five most popular phones sold in the US and tested them at a highly respected German laboratory. Four out of the five phones tested were above the SAR limit. One thing is for certain, similar to the case of cigarette smoking, it will take several tests and many years before the effects of radio frequency radiation on the human body are known.
Every day, we’re swimming in a sea of electromagnetic radiation (EMR) produced by electrical appliances, power lines, wiring in buildings, and a slew of other technologies that are part of modern life. From the dishwasher and microwave oven in the kitchen and the clock radio next to your bed, to the cellular phone you hold to your ear—sometimes for hours each day—exposure to EMR is growing and becoming a serious health threat.
Forward your cell phone to landlines whenever you are at home, then power off the cell phone without missing a call. Biological effects can be related to both strength of cell phone radiation dose and duration of exposure, so consider whether or not your communication is urgent. Remember: Use a corded home landline (not a home cordless phone, because cordless phones use electromagnetic microwave technology just like cell phones). Most cordless phone base stations constantly emit microwave radiation regardless whether or not any connected handset is in use. The cordless phone handsets also emit microwave radiation. Corded landlines have no radiation emissions and are the best choice.
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).