1This portable fish finders detects and shows fish location with water depth, short and tall weeds, sand and rocks. 2The color LCD display of the fish finder is visible under sunshine. Backlight enable the fishing sonar for night fishing. 3Five assistant settings are available on this portable fish finders. Adjustable sensitivity, battery save mode, backlight mode, fish and fish school alarm and battery indicator. 4The portable fish finders works with wired transducer with a 25ft cable wire. The depth unit can be switched from M to FT if long press enter button for 5 seconds. 5The detecting depth range of the fishing sonar is from 3ft(1m) to 328ft (100m) with 45detecting degree. 6This portable depth finder uses 4 x AAA batteries(Not included). Normally this fish finders for kayaks can continue working for 45hours with new batteries. 7Multifunction, you can use this portable depth finder for various fishing occasion like boat fishing, kayak fishing, sea fishing, ice fishing and so on.