With the Bushnell Bear Grylls BackTrack GPS Personal Location Finder, you'll always find your way back. Mark your starting point with the push of a button and the BackTrack shows you how to return to that exact point, no matter how far you ventured off. The durable, weather-resistant BackTrack stores up to three locations and uses its high-sensitivity SiRF Star III GPS receiver and self-calibrating digital compass to direct you back. Included lanyard is easy to attach to your backpack or belt loop. Backlit display is easy to read even at night. Requires 2 AAA batteries (not included).