For boaters and watersports enthusiasts who want to run with the best, the rugged GPSMAP 78sc includes preloaded U.S. coastal charts and features a 3-axis compass, barometric altimeter, crisp color mapping, a high-sensitivity receiver, new molded rubber side grips, plus a microSD card slot for loading additional maps. And it floats.. GPSMAP 78sc comes with built-in BlueChart g2 coastal charts and a worldwide basemap with imagery - perfect for all your outdoor pursuits. Map detail includes shorelines, depth contours, navaids, harbors, marinas and more for the U.S. and Bahamas. And, like the rest of the 78-series, 78sc is IPX7 waterproof and even floats in water.