the SD card holds the map information for that area
If Sat Nav unit is SD card type ,
then it should be noted when inventorying/inspecting into pinnacle and advertising on ebay if the SD cad is missing
If unit doesn't have SD Card then maps wont show
What can buyer do if SD Card is missing ?
These are available aftermarket (can be bought on ebay ) or genuine as replacement units and range is cost from $40 to $400