they dont make it simple with what is and what can be provided. internal external antenna. transducers with different part numbers. then come the navonics loaded or not loaded. then come the lake charts then the marine charts. gold, platinum, platinum plus and yes a silver. i fish the nh and maine coastline to 30 miles out. i fish lake winnipasauke early and late salmon. would like to buy one time, the right equipment. also have cannon downriggers, needs the hummingbird. if you have one lets talk, if you have opinions lets talk. thanks.