I have a humminbird helix 10 inch g3 for sale in the fishwrecked for sale colum, the unit is one and a half years old, as new with side scan transducer. The unit is a combo sounder and chart plotter with an included map chip navionics . A current model with inbuilt contour mapping which records all bottom sounder info and inserts this to your mapping chip permanantly. Selling at one third replacement cost. I live in Whitfords where you can inspect and test. I am retired so home most of the time. The new generation Hummingbirds are a true salt water unit with the best sidescan in the recreational market.