Humminbird has 3 levels of products currently available, and offer support for several now discontinued models.
Solix are the top of the line Humminbird Fishfinders. They have bright, clear screens, designed to be viewed in harsh sunlight with polarized glasses. The Solix series have a sensitive touchscreen and buttons on the side for operation even in rough conditions. Every Solix has a ethernet screw port on the back allowing direct networking between units, or to a 360 transducer. Any Solix on the networking with Mega Imaging will share it with all other units on the network, regardless of what imaging capabilities the other units have. These units are built on a new operating system, limiting the networking available between them and Helix/700/800/900/1000 units.
Helix series fishfinders are the staple of the Humminbird brand. They offer enhanced networking, upgraded basemaps, chirp sounder, and megaimaging for the clearest returns possible.