FYI, I can't remember the last time the battery went dead on my compass.

Also, my big red parka-easy to spot from a helicopter. And yes, I am serious about both of these points. A map and compass will outlast any device unless you have brought a charger of some sort and having bright clothes or some sort of orange panel will aid anyone looking for you. I used to carry a small flare gun that came in an emergency pouch that may have come from Campmor. It had the flare, a mirror, a few other items.