Fish Finder and Depth Finder : It is a portable fish finder that could display approximate fish location and water depth. The sonar transducer can be attached to the hull of kayak or boat in order to understand the changing of water depth when you are moving by. The water depth detection range is between 3ft(1m) and 328ft (100m) when the transducer is completely immersed in the water. Helpful Data Display : Besides fish depth and water depth, the handheld fish finder will also display short & tall weeds, sand & rocks on the bottom. Meanwhile, the measurement unit of the depth can be freely switched by feet or meter. The display is also visible in sunshine or darkness by turning on the back light. Handheld & Portable : The size of kayak fishfinder is designed for just one hand held. You will find a neck strap in the package which allows you to wear it around neck when you are busy on the kayak or boat. Meanwhile, 5 levels sensitivity adjustment makes fishing possible both in clear water or turbid. Fish & Fish Schools Alarm : Once the toss fish finder transducer into the water and turn on the display unit, you will get alarms when fish or fishing schools passing by. The portable fish finder can be working continuously for at least 4-5 hours with brand new battery. It can be working even longer by turning on battery save mode.