The TOPO Australia SD has Special features include:

Coverage for all of Australia
Terrain contours at 20 metres approximating 1:100K maps
Routable road content provided by NAVTEQ and HEMA; includes everything from urban streets to national highways including famous outback routes such as Birdsville, Strezelecki, Oodnadatta, Canning Stock and more
Railways, tracks, paths and trails; includes 4WD destinations
Water coverage of perennial and seasonal lakes, rivers and streams
Searchable points of interest in urban and outback areas including lodging, entertainment, food, airports, parks, campsites, caravan parks and more, provided by NAVTEQ and HEMA
Searchable landmarks, place names and cities such as mountains, water bodies, regions and more
National, regional and local park coverage
Elevation profiling and 3-D view, DEM shading on compatible units allows you to estimate terrain difficulty