The HOOK series combines the benefits of CHIRP sonar with built-in Broadband fishfinder technologies to give you a clear and complete view of the underwater environment beneath your boat. Using the Lowrance HDI Skimmer transducer, these CHIRP sonars provide the capabilities to produce medium and high CHIRP sonar ranges. CHIRP sonar technology provides greater sensitivity, improved target resolution, and superior noise rejection for clearer, easy-to-see bait fish and game fish targets. The HOOK-4x also features Advanced Signal Processing (ASP) which reduces the need to manually adjust settings to see fish, structure, and bottom detail more clearly. TrackBack lets you review recorded sonar history including structure, transitions, or fish targets. The new page selector menu provides quick access to all features using one-thumb operation. The multi-window display lets you quickl.