I was about to post a link to a previous thread that discussed devices such as the inreach, but I see that Tiger 4x4 has already done that. I won't repeat my comments that are already on that thread, but I would like to stress that mine (An inreach explorer model) has worked very well for me. My son rode a mountain bike on the Tour Divide Mountain Bike race last summer. For almost twenty days with it mounted on his handlebars over some of the roughest trails in the mountains, it continued to work flawlessly. There are shortcomings to be aware of, one being that a clear line of sight is needed to the sky for it to access the satellites and even with that, it does not necessarily act instantly. Another is that in order for someone to contact you, you must have messaged them so that they can reply, or use the link to contact you if necessary.