When it comes to emergencies, SPOT got nothing on Resqlinq.
The latter has 5 years shelf life, no subscription fees, communicates distress signal with GPS coordinates to a much larger array of low orbit Search and Resque satellites(so works better in canyons), if GPS fails to acquire position (again in a canyon) the satellites can also figure out an approximate position using Doppler effect and trickery with multiple receivers, has a homing beacon for S&R aircrafts, has a strobe light, is buyoant and water-sealed.
The latter has 5 years shelf life, no subscription fees, communicates distress signal with GPS coordinates to a much larger array of low orbit Search and Resque satellites(so works better in canyons), if GPS fails to acquire position (again in a canyon) the satellites can also figure out an approximate position using Doppler effect and trickery with multiple receivers, has a homing beacon for S&R aircrafts, has a strobe light, is buyoant and water-sealed.