The palm-size Garmin inReach Mini satellite communicator provides off-the-grid contact even when size and weight matter. At only 3.5 oz, it has 2-way messaging, tracking and SOS capabilities.
We got the Garmin inReach Mini when we did our first bike-packing trip from Spearfish to the Devil's Tower. We wanted the security to know that if an accident happened while on remote roads in the national forrest, we could get help even if we didn't have cell phone service. Now we take it along anytime we are doing long, unknown or remote routes- just in case, and for a sense of security and peace of mind.