Through this product, you can quickly confirm whether there are fish here, the position/quantity/depth of the fish, and it is a good helper for fishing masters Working principle: Use the ultrasonic transducer to transmit the signal, propagate through the air or water, use the ultrasonic wave to contact the object in the water to feedback the signal, and then process it through the internal processor and display it on the screen Product Features: Simulation demonstration mode, convenient for users to understand how to use LCD display Depth detection range 100 meters, degree 10 cm User definable units of measure: meters or feet Light green screen backlight battery saving mode High/Low Sensitivity Settings Fish Position Depth Scale Probe: can be floated on the water or installed on the side of the ship for use 200KHz sonar frequency 45 degree probe detection angle Powered by 4 AAA batteries, but not included in the item IPX4 waterproof design Display: TN/ANTI-UV LCD Backlight: Green LED Power Requires: 4 AAA alkaline batteries Units of measurement: feet and meters Sensor beam angle: 45 degrees Maximum depth range: 100M Minimum depth range: 0.6M Operating Temperature: -4F to 158F (-20C-70C) Dimensions: 12cm x 6.8cm x 3.1cm Weight: 578 g