Explorer 657 Northstar’s 5" high resolution VGA Chartplotter/Fishfinder combo with Fuel Management and AIS functionality.The built-in 32 MB regional background map still offers reliable entry-level use, waiting to be enhanced with C‑Map’s latest cartography: NT MAX™. With a 640 x 480 pixel screen, your display becomes 4 times sharper than the Explorer 650, being a truly impressive, bright and highly functional addition to your boat.With a range of optional fuel add-ons, the Explorer 657 is a powerful travel tool for your boat.