Backpacker April 09 calls the Garmin Oregon 400t the ultimate GPS: simple enough for beginners, wonky enough for experts, powerful enough for all.. Preloaded topographic maps serve up vibrant 3D walk the trail mapping and Worldwide Digital Elevation Model DEM basemap with shaded relief. Map details include national, state and local parks and forests, terrain contours, elevation information, trails, rivers, lakes and points of interest. Large, sunlight-readable screen offers crystal-clear colors and high-resolution images. Easy, intuitive touchscreen operation is fun and simple to use. Waterproof MicroSD card slot for storing additional data accepts Garmin MapSource and BlueChart data cards and software. Built-in electronic compass and barometric altimeter provide additional navigational aid. Supports Geocaching.com GPX files for downloading detailed geocache descriptions, terrain, difficulty and hints directly into GPS unit. Groundspeaks Wherigo Player application comes pre-installed and includes an instructional tutorial learn more at www.wherigo.com. Built-in basemap stores up to 1,000 waypoints, 50 routes and 20 tracks with up to 10,000 points Digital Elevation Model shading enhances map view. Enjoy effortless sharing of waypoints, tracks, routes and geocache locations between Oregon and Colorado series units with ANT wireless communication function. High sensitivity receiver and HotFix satellite prediction provide rapid first fix and help maintain signal, even in urban canyons and under dense foliage. WAAS Wide Area Augmentation System enabled receiver delivers accuracy to within 10 ft. in North America. Offers configurable profiles for end use: auto, marine, recreation, fitness and geocaching. Operates on two AA batteries sold separately.