There aren't any significant differences between the older HELIX 5 DI model and the new HELIX 5 DI G2. However, since Humminbird brought a new generation of HELIX 5 units, they also released a Down Imaging and a Sonar Only unit. Therefore, since it's a newer model, the G2 will probably replace the older HELIX 5 DI unit. With regards to the specs of this unit, the HELIX 5 DI … [Read more...] about Humminbird Fish Finder HELIX 5 DI G2 Review