So you're on a hike and recording your track, and need to check your GPS device regularly to enter waypoints etc. Where to keep your GPS unit? In your pocket, or even a belt clip, your body can block the signal some of the time. The top pocket of your backpack works fine, but not if you need to get at the unit regularly.This device secures to a shoulder strap on your backpack. This places it high on your body for relatively unobstructed GPS signals. It is detached and reattached by a simple hook-and-loop patch. Super convenient.