although never mention in the product description , Garmin GPS unit in this general category be NOT Mac compatible . they work only with Windows . for such a well-known brand , this be surprising and extremely inconvenient . the ramification of this be that the gp work fine in the field , but waypoint transfer and map must be do on a pc platform . do not have a pc ? you be out of luck . something I wish I have know before spend several hundred dollar on the receiver .