The iPaq PDA is a Compaq/HP 3850. The GPS sleeve is a Navman CoPilot with a 128 Meg flash card (for storing map data). The photo on the right shows the two units combined. The short barrel at the top is the integrated GPS antenna. The entire unit is powered by the PDA's internal battery.
This iPaq PDA was a good choice for use as a GPS due to the color screen .... it was designed to be clearly visible in daylight, a condition that is typical for GPS use. The display also has sufficient resolution to allow the proper rendering of fairly detailed graphics... a key for good looking maps.
Since the software has gone through several release, it was fairly mature and feature rich. Driving directions can be displayed as a list or tracked on the map. A voice prompts the driver when it is time to turn. There are other information displayed to inform the driver on the trip's progress.
The maps have to be loaded via a computer, but by purchasing a 128 Meg flash card ($30), about half of the continental US can be loaded on the unit... certainly enough for most day-to-day driving!