I don't have one in any of my vehicles but I use Garmin on my boat. It is a combination GPS and Chartplotter. I got it cheap because we are a Garmin dealer at work. I also purchased the computer program with it so I can plot my courses and enter all waypoints from the comfort of home. After the waypoints are entered I download them into the unit and go. It is an excellent program/unit. I can also download updates direct from the Garmin website.