The leader in sonar and mapping technology has taken GPS mapping and fused it with Marcum's legendary sonar platform to give you the all-new MX-7GPSLI. The lithium-powered sonar/GPS combination unit has a lighting-fast sonar reaction time that's been a hallmark of the Marcum brand. Gone are the days of using an open-water sonar simply to get GPS capability. This one is build specifically for the rigors and mechanics of hardwater fishing. Like MarCum's flagship LX-5 flasher, the MX-7LI dual-beam precision engine offers both the widest and narrowest viewing angles on the market. A 20 degrees ultra-wide angle sonar cone sees fish further to the sides, giving you an advantage for both finding AND catching. And 8 degrees Narrow Beam Transducer (NBT) targets only the fish directly beneath you to overcome standard sonar issues on steep breaks. And industry-leading A 1/2" target separation lets you discerning fish from the bottom, fish from other fish, and fish from your bait. 12 patented interference rejection settings double your ability to tune out noise to give you visible clarity and acuity. Zoom anywhere in the water column to target bottom-dwelling fish like walleyes and suspended species like crappies. And get precise positional accuracy with its internal GPS receiver that'll take you back to your favorite spot with smoother tracking and exacting detail. Navionics Basemap mapping gives you more coverage of more lakes from proprietary mapping and public data, so you'll never be left out in the cold. And a Micro SD card slot gives you the option to use more detailed Navionics mapping, or running the freshest software updates. Purchase the optional open-water ducer (sold separately), and you'll be able to bring this system from hardwater to open water for year-round use. Advanced Lithium Shuttle Battery Power Every MX-7 comes standard with a MarCum Brute 12V 10Ah Lithium LifePO4 battery, the new standard in lightweight, f