I bought a SPOT Satellite Personal Tracker.
SPOT a satellite personal tracker could be a life saver for those that ride in the backcountry where cell service is not available. I purchased one of these units recently and have tested it out on a couple of rides and it worked as advertised. The unit can send pre-programed messages to email addresses and/or cell phones that you specify and can also do live tracking where your family/friends can watch your movement on Google Earth. I now carry this unit with me whenever I know I will be riding in areas where cell coverage is questionable.
The unit has 4 modes of operation:
Send OK message - sends an email and/or cellphone message to those you specify letting everyone know you are OK. The message includes GPS coordinates of your location and also a link for Goggle Maps so the recipients can see exactly where you are.
Send Help Message - sends an email and/or cell phone message to those you specify that you need non-emergency help. The message includes GPS coordinates of your location and also a link for Goggle Maps so the recipients can see exactly where you are.
Send 911 message - sends a message to a control center that you need emergency help. The message includes GPS coordinates of your location and so emergency help can be dispatched to your location.
Live Tracking - allows anyone you give access to watch your movement on Google Earth in real time.
Read more about it here:
SPOT Satellite Personal Tracker WebsiteThe unit is small and has a belt-clip or what I do is carry it in my jacket chest pocket.