SPOT Gen4

Backcountry.com says:
Through the years, devices like the SPOT Gen4 Satellite GPS Messenger have become essential when venturing into remote areas. What we love about this particular offering from SPOT is its compact design, affordability, and host of smart, useful features—all of which make it possible to stay in contact whether you’re criss-crossing a rugged mountain range or just road tripping in a remote part of the country. The Gen4 boasts an S. O. S feature that can be used to alert rescue teams in the event of an emergency, but it also can be used to transmit tracking info, pre-programmed check-in messages, custom messages, and a help feature, so you can let up to ten contacts know where you are and if you need help in the event of a non-life-threatening situation.