I have a garmin GPS/ the Capt'n charting program. Works great. I have taken it to the Islands when sailing the US Spanish Islands and use it in the Great Lakes. I have a combination 12 volt/gps/Computer cord. the only thing that would make it better is a portable GPS antenna. The cord is long enough for me to put the gps up on the coach roof but the antenna would be an improvement. Great portability.