Magellan Meridian Marine Waterproof Hiking GPS 12-channel GPS unit with 16 MB marine base map Built-in database of U.S. marine navaids including fixed navaids, buoys, obstructions, wrecks, and lighthouses Secure Digital memory-card slot for expanded storage Waterproof; rugged, ergonomic design Oversize gray-scale display with backlight; backlit keypad