In a road image analyzing apparatus capable of obviously and rapidly distinguishing a road marking from a guardrail and capable of obtaining precise position information, a pre-processing unit defines sub-areas to main image data obtained by an image pickup unit, and an edge extracting unit extracts an edge component in each of the sub-areas. Control circuitry in the wireless electronic device may adjust antenna switching circuitry so that the device repeatedly cycles through use of each of the antennas. The anti-rotation leg preserves the orientation of the pressure plate and prevents a speed wire arm from being deformed when removing a speed wired wire from the device. The invention also provides retainer assemblies that include ball-lock assemblies, as well as methods of producing retainer assemblies, which methods include providing ball-lock assemblies.