YUFENG Wireless Fish Finder Portable Sonar Echo Sounder Display water temperature and depth, fish depth and location, weed detector, bottom contour detector, sensitivity, and battery strength. Audio fish alarm alerts you when fish have been found. Backlight LCD for clear reading even when fishing at night or in overcast weather. Suitable for fishing at the boat and on ice. Can be used in ocean, river, and lake, it shows the grass, rock, sand in the sea.