Lowarnce MARK-4 HDI Combo Plotter/Fish finder.The MArk-4 HDI is an easy-to-use 4.3-inch monochrome fish finder/chart plotter with Hybrid Dual Imaging that combines Broadband Sounder with Down Scan Imaging technology, super-bright, LED-backlit grayscale display, built-in GPS antenna and high-definition mapping. The Elite-4 HDI offers a full selection of today"s top-selling fish finder and chart plotter features that are easy to access and operate -- all at a surprisingly affordable price. Enjoy exclusive Hybrid Dual Imaging (HDI) with the power of two award-winning technologies combined to provide the best possible view beneath your boat. It has a 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 Nautica Insight PRO and HD, Navionics Gold and Hot Maps Premium, Fishing Hotspots PRO and Jeppesen C-Map Max-N. Create your own map from real sonar data that you record with Insight Genesis, and use Down Scan Overlay technology to overlay Down Scan Imaging onto the Broadband Sounder. Advanced Signal Processing (ASP) reduces the need to manually adjust settings to see fish, structure and bottom detail more clearly, and TrackBack allows you to review recorded sonar history, including structure, transitions or fish targets, then pinpoint locations with a waypoint. The new easy-to-use page selector menu provides quick access to all features using one-thumb operation, and the Multi-Window Display lets you quickly and easily choose from pre-set page layouts, including a three-panel view with chart, Broadband Sounder, and Down Scan Imaging. All this is supported by the Lowrance Advantage Service program. Dimensions: 6.6"H x 3.8"W x 2.2"D. Warranty: One year parts and labor. In the box: Elite-4 HDI, transom mount transducer, mounting bracket, power cord, owner"s manual.