We appreciated the slightly gritty, frictionless surface of the 3.1 x 1.7-inch touchpad, and were able to navigate the desktop with great accuracy. We also liked the backlighting on the keyboard, which is adjustable in 25-percent increments. The flat, medium-sized keys are smudge- and fingerprint-prone, but they provided firm feedback with little flex. This time, the port covers remained closed, and the E6420 continued running normally.Ĭlick to EnlargeThe black matte full-size backlit keyboard on the E6420 XFR provided a very comfortable typing experience. Then, with the notebook turned on and open, we dropped it twice from a height of three feet. While some of the port covers popped open, the notebook didn't suffer any damage, and started up normally. With the notebook turned off and closed, we dropped it twice from a height of 6 feet. And if that wasn't enough, the E6420 XFR can operate in an explosive environment-for example, a room saturated with gasoline fumes-without igniting the air around it. The notebook can also endure 5.8 inches of rain and 70-mph winds while open and operating, as well as temperatures ranging from -20 degrees Fahrenheit to 145 degrees. When it's open and turned on, the machine can survive a fall from 3 feet. The E6420 XFR can withstand drops from 6 feet while closed and off. These components combine to create what Dell calls its Ballistic Armor, which enables the notebook to withstand rigorous MIL-STD-810G and MIL-STD-461F testing. Dell says the E6420 XFR can stay cool under pressure without the use of external vents, thanks to a combination of conductive cooling, thermal pipes, and a sealed fan chamber. The E6420 is able to operate in extreme temperatures thanks to its QuadCool thermal technology. When closed, the port doors seal completely thanks to compression gasketing designed to keep water and dust from the notebook's interior. Click to EnlargeSimilar to the E6400 XFR's design, all ports and slots on the E6420 XFR are protected by doors using PrimoSeal technology, which has an industry rating of IP-65.