Venterior Portable Fish Finder Rechargeable & Wireless Sonar Sensor Fishfinder Depth Locator with Fish Size, Water Temperature, Dot Matrix 40m Range, 80m Distance Wireless and rechargeable: No more long&heavy cable for transducer. The body and the sensor both are rechargeable. Not need to buy battery. Display: Water Depth, Temperature, Power Indicator, Simulation Mode, Bottom Contour, Depth Range, Depth Scale, Fish Icon (different size), Water Line. No need to drill hole in your boat hull to install the sensor any more. Two small holes on the wireless sensor allow you to tether with your fishing line and cast it onto water as far as you want. Wireless Sensor Coverage: 90 degrees beam angle. Depth Range: 2-120Ft/0.6-36M The unit can remember before setting when you turn it off. Depth and Temperature units can be changed according you need. Note: 1. Choose English when the unit is turned on within 5 seconds; 2. It will turn off if depth display reads "--" for 5 minutes for power saving. 3. Please allow several seconds for the unit to update the water depth when you throw the yellow transmitter onto water.