Conclusion
After spending a couple of weeks using the Navman 3420 GPS sleeve to guide me to and from various points on Oahu I feel that I can safely say that the Navman is a great GPS navigation option. The device comes with all the necessary software and hardware for use in your car. This hardware includes the GPS sleeve, a holster, and an in-car charger. The software that comes with the device is extremely accurate, and most of the map software that I have tested doesn't have great coverage of Hawaii.
If you're looking for high quality GPS navigation for your car without the high price tag the Navman GPS system is definitely something worth looking into. It offers easy to use navigation to keep you on course. The Navman 3420 GPS Sleeve scores 4.9 out of 5.