There are four simple buttons and four distince modes:
*** Alert 9-1-1, a distress alert with location that goes to a emergency control center
*** Help, which sends a text message and/or email to up to four individuals to let them know you’re ready for pick-up or whatever you’ve prearranged
*** SPOTchecking, which notifies pre-set friends as to your location and that you’re ok.
*** SPOTcasting, same as SPOTchecking, except it’s automatically updated every 10′.

The batteries last for about a year if you have it turned on. That’s awesome battery life. If you someday have to use the 911 service, your emergency message will go directly to the “GEOS Global Command and Control Center” in Houston, Texas, operated by SPOT’s partner, GEOS Alliance Travel Safety Group. They’ll try to call up your contact numbers to confirm that it’s not a false alert… but if they can’t reach you, they act. I mean… they send in hum-vees or choppers or snow shoes or skis… whatever it takes. In fact, if you pay an extra $8, they’ll basically come get you *wherever* you are in the world. Bail you out. It’s kind of like having your own CTU and you’re Jack Bauer. :-) If something changes and the guys stop shooting at you, you can always use the 911-cancel feature to let them know you’re ok. They’ll call back the cavalry. If you don’t cancel, it keeps sending an alert every 5 minutes until the batteries go dead — about 7 days later. Spotcasting mode sends an “I’m ok” update and location every 10′ for 14 days. You can send about 1900 Spotchecking messages before the batteries go down.