This waterproof switch allows you to quickly and easily connect up to five Ethernet items. Use it to link multiple Humminbird head units, share transducers, add an NMEA 2000 network or step up to the Humminbird Radar. With so many options and even more to come, the possibilities are endless. The purchase of Ethernet cables and the AS EC QDE is required depending on the number of devices you plan to add to this switch and which models. All 8x9ci, 9x9ci and 11x9ci models require the AS EC QDE to network.