Humminbird Helix 15 Chirp Review The new Humminbird Helix 15 CHIRP G4 Sonar features an expansive display to take full advantage of all the latest technology, including MEGA Side Imaging+ (selected models), Mega Down Imaging+, Dual Spectrum Chirp sonars and internal GPS with Basemap. This allows anglers not only automatic charting capabilities but also Wi-Fi…