The Lowrance Globalmap 840C is a large-screen GPS unit that can be easily seen when moving quickly both on- and off-road. In general the large-screen marine units are more expensive than their smaller-screen brethren, but for most people who buy these it is the last GPS they will ever buy for a Jeep. Both the Garmin and the Lowrance units are bulletproof, and we’ve had no problems with the reliability of either over the years. One bummer as compared to the smaller unit is that if you like hiking and Jeeping, you are out of luck because they aren’t intended to be man-portable. And if you want to use it for on-road navigation, you might end up more bald than Hazel because all it does is draw a straight line from you to your destination.