Furunos network sounders turn any NavNet display into a powerful fishfinder. You can split the screen with any other NavNet features like: Radar, Chart Plotter, NavData and even Video depending on which NavNet unit you have. The DFF3 utilizes Furunos Free Synthesizer (FFS) transceiver, which allows you to select the operating frequency among 28 kHz, 38 kHz, 50 kHz, 88 kHz, 107 kHz, and 200 kHz. You can also select output power from 1 kW, 2 kW, and 3 kW RMS depending on the transducer. Three zoom functions are offered: marker zoom; bottom zoom; and bottom lock expansion; in addition to the standard sounder dispaly mode. There are audio and visual alarms for preset water depth, fish echoes or water temperature.