I used one while volunteering with the NPS at a remote location for 6 months. It connects with the Garmin app so you can text from your phone vs the device. Garmin also has downloadable maps that are compatible with the app and device. Fortunately I never had to use it in an emergency. Another advantage from what I was told is the satellite system Garmin uses vs the Spot system which can be slower to link up with do to its positioning in orbit