Personal Locator Beacon; basically a back-up emergency contact device. You register it with the National Search and Rescue (Canadian Military) who it sends an SOS signal to if activated. The signal is far more reliable than spot, there is no activation or service fees, and you can count on Canadians coordinating your rescue wherever you are in the world.
There are even one or two that for a lower fee than spot can be used to send I'm okay messages to people when you're out in the bush.
What I have (or at least the previous version); hopefully I'll never need to know how good it is.