Eoncore Portable Wireless LCD Fish Finder Depth Sonar Sounder Sensor Alarm Transducer Fishfinder 130Feet (40m) Blue This product is designed for fishing liker. The unit can be used in the river, the lake, or the sea It can help you find out the fish and measure the depth of the water, Especially it can bring pleasure to you in fishing Feature depth readout, fish alarm, selectable sensitivity, fish depth scale, etc. Can read depth of fish and water, display the rock or aquatic plant at the bottom Sensor auto power off when out of water