Garmin GPSMAP 820xs with Base map, without TransducerModel Number: 010-01180-018" Keyed Chartplotter/Sonar Combo for Cruising, Sailing or FishingThe GPSMAP 820xs keyed chartplotter/sonar combo has a 8" color SVGA display and comes with preloaded U.S. LakeVu HD and BlueChart g2 coastal maps. HD-ID 1 kW sonar, CHIRP and DownVu with CHIRP sonar technology are built-in allowing you the flexibility to choose from several optional transducers.The built-in sonar capabilities of the GPSMAP 820xs , including 1 kW traditional, CHIRP and all-in-one HD-ID/DownVu scanning sonar with CHIRP technology. GPSMAP 820xs displays crystal-clear sonar images detailing fishing hot spots, ship wreckage or a diving location. With Garmin CHIRP technology, you get remarkable target separation and resolution at extraordinary depths, and can dial into specific frequencies to target certain species of sport fish. Bottom contours are more visible, even at speed, and signal noise can be suppressed at greater depths to provide a more timely interpretation of what's below for safer navigation and better fishing.The GPSMAP 820xs comes preloaded with a worldwide base map. It's compatible with optional mapping, LakeVu HD Ultra with MaxDef Lakes and BlueChart g2 Vision.High-sensitivity internal 10 Hz GPS/GLONASS provides position and heading updates 10 times per second. It displays fluid on-screen location and proves to be incredibly accurate when marking 5,000 waypoints and navigating.