Man - I just spent over two hours going Round and round -- I Just purchased a Humminbird Helix 7 GPS SI -- I was looking at Lake Master for the Card I needed for it, I couldnt get to the info or the Lake List for the South Card. In Louisiana there is a short list of Lakes and D'Arbonne Not on their List. A Couple of my friends have Cards in their Sonar units and they do have the Contour lines .. I heard that the Platnium card is Compatable, I just have not looked at Navonics as yet... I am Intrested .. I purchased On Line and the new unit will Probably be Here Monday