Features:

SOS (was 911): Use this function In the event of a life threatening or other critical emergency to notify emergency services of your GPS location and that you need assistance. The GEOS International Emergency Response Center alerts the appropriate agencies worldwide - for example contacting 9-1-1 responders in North America, 1-1-2 responders in Europe and AMSA in Australia.

Help: In the event of a non-life threatening emergency, you can use this function to notify your personal contacts that you need assistance.
 

Check-in/OK: This feature allows you to let your friends and family know that all is OK with a pre-programmed message along with your GPS location. With a push of a button a message is sent via email or SMS to up to 10 pre-determined contacts and your waypoint is stored in your SPOT account for later reference. Your stored waypoints can be easily integrated into a SPOT Shared Page.

Custom Message: This feature allows you to let your friends and family now receive a custom message along with your GPS location with a push of a button. Use this feature as a secondary OK message or specialized Help message.

Track Progress: This feature allows you to send and save your location and allow contacts to track your progress in near real time using Google Maps. With your SPOT account you have the ability to set up a SPOT Shared Page which allows you to show your SPOT GPS locations to others on a Google Map.
 

Coverage:
SPOT works around the world, including virtually all of North America, Europe and Australia, portions of South America, Northern Africa and Northeastern Asia, and hundreds or thousands of miles offshore of these areas.

Specs:
Height: 95 mm
Width:  66 mm
Thickness: 25 mm
Weight: 147g
Operating Temp: -30C to 60C
Operating Altitude: -100m to +6,500m (-328ft to +21,320ft)
Humidity Rated: MIL-STD-810F, Method 507.3, 95% to 100% cond.
Vibration Rated: Per SAE J1455
Battery
Type: 3 x AAA Lithium
Standby mode: 94.7 days
SOS/HELP: 2.8 days
Track Progress: 4.3 days
Check OK/Custom Messages: 350 messages

Mandatory service - US$115 per year basic satellite service subscription includes:
SOS (was 911):
Dispatch emergency responders to your exact location
CHECK IN (OK):
Let contacts know where you are and that you're okay
CUSTOM MESSAGE:
Sends a custom message along with your GPS location with a push of a button.
ASK FOR HELP:
Request help from friends and family at your exact location

Annual subscription includes unlimited emails and 200 SMS (additional SMS charged at US$0.10/SMS)

Optional Service:
TRACK PROGRESS:
US$49.99/yr Tracking Upgrade Option
Send and save your location and allow contacts to track your progress using Google Maps.