Alpha 100 handheld features a 3-Inch glove-friendly color touchscreen * Track and train a combination of twenty TT 10 dog devices ( TT 10 devices sold seperately) or Alpha 100 handhelds simultaneously from up to 9 miles away * Includes preloaded TOPO U.S. 100K mapping for terrain contours, topo elevations, summits, parks, coastlines, rivers, lakes and more * Supports optional map data - TOPO U.S. 24K, BirdsEye Satellite Imagery, autorouting with City Navigator, and Garmin Custom Maps * Built-in 3-axis electronic compass and barometric altimeter