The SPOT looks like a big orange walky-talky; it's light, it fits in the palm of your hand, and it is very orange. The thick black plastic buttons and grips on the side add to its rugged feel. The AA batteries required for the device to work are included in the package, along with a user guide to help you get used to it.

Because the SPOT is a satellite messenger, it must acquire a signal before you can really start using it; you can't turn it on and expect it to work. You need to leave it out in the open (or at least somewhere with skyward view) for a good 10 to 20 minutes before it's able to send messages. Its size and shape do make it obvious that the SPOT is a device designed for safety--the bright-orange exterior is impossible to mistake, and the fact that there are only four buttons (on/off, check-in, help, and 911) make the device incredibly simple to use, even in an emergency.

The SPOT device is only half of the equation. The other half is your SPOT profile, which you can manage from any computer with Web access. You get an ID number with your SPOT, and with it you can go to the company's Web site, log in, register your device, and configure your alerts. The SPOT can send three different types of messages: check-in messages, help requests, and emergency/911 messages. Each message is sent with information to help find your location, including your latitude and longitude, your device number, the nearest town to your location and how far away it is, and a link to a Google Map with your position indicated on the map.

Check-in messages are just over 100 characters and can be sent to any e-mail address or mobile device. Type in the message you want sent when you check in from the trail, and add your e-mail address and telephone number (the service supports most major U.S. and international cellular carriers). Once you save your settings, each time you press the check-in button on the SPOT, your message will be e-mailed to the address you specified and sent via SMS to the mobile number you provided. You can always visit the SPOT Web site to see any messages the SPOT device has sent, whether they're messages for help, emergency messages, check-in messages, or even the test messages that the device sends to verify its connection to the satellite network.

Help messages are similar to check-in messages; they're designed for when you need assistance but may not want to call emergency services--for example, if your tire is flat and you're in the middle of nowhere, or if you're lost but you know you're not terribly far from civilization. The help message can also be customized and send to the same or a different e-mail address or mobile number. Finally, the emergency/911 button sends a message directly to SPOT's emergency service provider. The provider contacts fire and rescue personnel in your vicinity and provides them with your most recent coordinates so they can find you.

I carried a SPOT messenger with me for several months, and while I thankfully was never faced with a life threatening situation where I had to use the SPOT, it definitely came in handy for a number of other things; I could see how people who may not be the outdoorsy types may find the SPOT useful. The device obviously is geared towards hikers, bikers, campers, and others who may be away from towns and cities for long periods of time, but the SPOT could also be useful for parents or families who are separating for vacations or long trips and want to be able to check in with one another without having to call or e-mail.

A colleague recently left on a long biking trip with a dozen other people, so while his safety is assured, his family may not be able to reach him, because he won't have a cellular signal. The SPOT could give him a device with one button to check in with them nightly to let them know that he's doing well and he's made progress along his planed route. But if something horrible did happen, the SPOT could save his life.

During my time with the SPOT, I used it periodically from my office and on my commute to work to see how quickly it would send a message with my exact position. In each case the SPOT was accurate enough that it would be easy to find me, and the pointer on the Google map was only a few meters from my actual location. The device is reliable enough that the service has been endorsed by "Survivorman" Les Stroud of Discovery Channel fame, who regularly strands himself in deserted locations with only his cameras and his wits to guide him to safety.

The SPOT device itself costs $169.99, and an annual subscription to the satellite tracking service is $99.99 per year. You can add such features to your tracking service as progress monitoring and search-and-rescue benefits for an additional cost.