TechwareLabs has published a review of the PowerMax Digital Antenna 4KMR-10A
A quote from the article:
PowerMax Digital Antenna 4KMR-10A Review
If you are tired of dropped cell phone calls or a lack of any signal while in certain areas then you might wantt o invest into a cell phone signal booster for your car. The 4KMR-10A by Digital Antennas boasts a 20+ mile range extender as well as several other features which include a lack of physical connection to your cell phone. Wire free you can be on the phone 20+ miles from the nearest cell phone towers range and make and receive calls. Sound interesting? Read our review and find out if this device actually works.
PowerMax Digital Antenna 4KMR-10A Review