Garmin echoMAP CHIRP 42dv without transducer Clearer scanning sonar - shows you more of what is in the water around your boat. This high-frequency sonar gives near-photographic images with detailed representations of objects, structure and fish. Chirp sonar - Chirp sends a continuous sweep of frequencies which provides a wider range of information. Chirp sonar is able to create crisper fish arches with better target separation. Built-in maps and charts - available with either U.S. Bluechart G2 charts, U.S. Lakev HD maps or Canada lakev HD maps. Clear scanning sonar - the CV Series comes with built-in 500 w Chirp traditional sonar and Chirp clearv scanning sonar. The SV Series offers all of the same Features Plus Chirp sidev scanning sonar. Best-in-class Internal 5 Hz GPS - Internal 5 Hz GPS updates position and heading 5 times per second to make marking and returning accurately to waypoints easier.