they are discontinued but you can still see and order on there website,go to the discontinued section and they are available there,they will accept the mapsource data cards,not sd cards,i have the 398c and it comes preloaded with inland lakes,dont know if the 178 does or not,i know boaters world carries them,or you can get the blank data card and get the mapsource cd and download only what you need in the card for your use