A mobile device contains a case to rigidly secure and protect components of the mobile device, especially against large shock forces that can occur when the mobile device is dropped. The case is typically formed using a material that is generally rigid, lightweight (i.e., less dense), and relatively inexpensive, such as magnesium. The case further comprises rigid sidewalls that surround the peripheral edges of the device display. The sidewalls are arranged to protect the display by absorbing incidental shock forces. The case further comprises a surface is configured as a platform to receive a keypad. The surface is arranged to prevent forces from being transmitted from the keypad to an internal print circuit board, which provides protection against the internal printed circuit board from being flexed to the point of failure. The mobile device may further comprise a boot that is slidably coupled to the frame.