The Fishfinder Blue Series is designed for offshore fishing enthusiasts. The Fishfinder 100 Blue operates at dual frequencies. With the 50200 k Hz transducer you can reach greater depths & get a wider viewing area. & you will see those returns on a crisp four-level grayscale screen for excellent separation & contrast. This seaworthy fishfinder is rugged & waterproof. But despite its tough exterior it is extremely easy to operate with features like a convenient adjustment bar that gives you access to the most commonly used fishing settings Fishfinder 100 Blue Surface mount feature Wiring adapter cable Transom mount transducer with temp Users manual Quick reference guide Features Display options Auto ranging 2X & 4X auto & manual zoom 3 Fish Symboland 153 sizes adjustment bar Alarms Deep water alarm shallow water alarm 3 size fish alarm battery low alarm Transducer auto-sense Automatically displays speed & temp data without menus See-Thruand 153 technology Shows weakstrong returns simultaneously Depth Control Gain DCGand 153 Automatically adjusts fishfinder sensitivity according to depth Power down backup of settings Customer settings not lost when unit is turned off Frequency 50200k Hz Depth 200 foot max depth