The second category of fishing for fish is considered the best. They are two or three-beam and the circle of review of them is extremely wide. In these echo sounders, water temperature sensors, alarms during the detected fish, meters of measuring the speed flow of water and many other pleasant modules are built -in. With this category of devices, the bottom of the reservoir can be considered, even moving in a motor boat. A strong signal is more clearly and clearer. The fish on the monitor is clearly separated from the surface of the bottom of the reservoir.