GT34UHD-THP Ultra HD Thru-Hull Transducer - PairUltra High-Definition Sonar System Thru-hull TransducerAdd stunningly clear Ultra High-Definition ClearVü and Ultra High-Definition SideVü scanning sonar images to your compatible chartplotter via the GCV 20 sonar module. It includes 3 arrays, including a downward-facing element element with frequencies ranging from 0.8 MHz 800 kHz to 1.2 MHz 1,200 kHz and its recommended for hulls with up to a 5-degree deadrise angle.Ultra High-Definition ClearV