Bought a coffee can sized transducer as recommended by friends. This dual frequency tranducer showed schools of bait at 30 mph, and worked phenemenal in shallow water. Switched back and forth from the 3 n 1 transducer to compare. The 3 n 1 didnt show a quarter of the fish in shallow water. The downscan and sidescan also worked better which was a pleasant surprise. All this in san francisco bay. Still learning with settings but this awesome.Anchovies, sandsharks and someone dropping down their line