Compact Signalling Mirror
A Signalling Mirror (otherwise called a Heliograph) is a must in any Go-Bag / Survival Kit.
This model of signal mirror is small, compact, and has a ball chain as a lanyard.
When used correctly, a mirror can reflect sunlight with life-saving accuracy (as far as 7 miles on a clear day) to alert potential rescuers of your location. In wilderness areas, your potential target will usually be a bush plane or helicopter, but a mirror can also be used to signal people or vehicles on the ground.