Lowrance Mark-4 CHIRP Fishfinder/Chartplotter. 4.3" Monochrome LCD with Pre-loaded Base map, 83/200 KHz and 455/800 KHz transom mount transducer. All-NEW, easy-to-use 4.3-inch fishfinder/chartplotter that combines CHIRP Sonar with DownScan Imaging technology, super-bright, LED-backlit grayscale display, built-in GPS antenna and high-definition mapping options. The Mark-4 CHIRP includes all of the proven features of the Mark-4 HDI Series with the addition of CHIRP sonar technology providing greater sensitivity, improved target resolution and superior noise rejection for clearer, easy-to-see bait fish and game fish targets all at a surprisingly affordable price. CHIRP sonar advantages: Easier to identify and distinguish bait and game fish targets. Better target identification at greater depths. Mark fish clearly at faster boat speeds. Exclusive Lowrance Elite-4 CHIRP advantages: Lowrance-exclusive, brilliant, high-resolution, 4.3-inch, LED-backlit display. CHIRP Sonar plus DownScan Imaging -- the power of todays leading fishfinder technologies combined to provide the best possible view beneath your boat. Highly accurate, built-in GPS antenna plus a detailed U.S. map featuring more than 3,000 lakes and rivers and coastal contours to 1,000 feet. Optional chart upgrades include Lake Insight and Nautic Insight PRO and HD, Navionics+, and HotMaps Premium, Fishing Hotspots PRO and Jespersen C-Map Max-N. DownScan Overlay technology overlays DownScan Imaging onto CHIRP Sonar. Advanced Signal Processing reduces the need to manually adjust settings to see fish, structure and bottom detail more clearly. TrackBack to review recorded sonar history including structure, transitions or fish targets, then pinpoint locations with a waypoint. New page selector menu with quick access to all features using one-thumb operation. Multi-Window Display lets you quickly choose from pre-set page layouts -- including a three-panel view with chart, CHIRP sonar ranges and DownScan Imaging.