This WIFI Fishfinder is based on Sonar technology. The WIFI transducer sends a sounds wave signal, the returned "echoes" are transmitted with WIFI technology to the iPhone, IPAD or other intelligent devices, then all the underwater information is displayed on the screen, including the water depth, water temperature, bottom contour, fish location, and depth. The WiFi range coverage is up to 50M and can connect with the maximum of 5 devices, but only one can be operated at a time. With a selection of 12 (twelve) languages: Russian, German, Dutch, Spanish, French, Japanese, Korean, Hungarian, Portuguese, Polish, English, Chinese. Features: Detects both fish location and depth Can be used as a fish finder and a depth sounder Built-in Water Temperature Sensor User select-able meter (m) or feet (ft) readings Display Water Temperature in °C or °F Display Fish Icon and Live-Update Water Bottom Detects and displays big and small fish or groups of fish Audible fish and depth alarm With Simulation mode With a 90-degree beam angle Fully waterproof design, it floats! Designed for amateur & professionals Powered by 3.7V built-in lithium battery Specifications: Sonar Frequency: 125KHZ Sonar Coverage: 90 degrees Depth Capability : 0.6M-45M (2feet - 130Feet) Power: 3.7V rechargeable lithium battery Running time: 5hours fully charge charger : 5V, 500mA WiFi range: 50M WiFi Frequency : 2.4GHz Charging indicator: red light Working indicator: blue light Set Includes: 1 x WiFi Fishfinder 1 x USB cable 1 x English Manual 1 x Neoprene Bag Standard Packaging Box