Mirrors are bright and usefull tools! A good friend of mine and I use them as means of communication while fly fishin! What I find interesting is even down here in the se in a river valley I can reflect the smallest beam of sunshine down to a man on a river fishing three hundred yards away. And he knows I'm headed back to camp with dinner in hand! We have kind of our own mirror fishing language!

And it's very effective!

Wile standing in the river you generally have a bit of visual up to the hill sides and can signal back or use some sort of sign language or hand gestures to signal back! A deflected sun been in your face catches your attention like nothing else on the backcountry compleately un natural !

No batteries! And mines pretty much indestructable

If you ever get something stuck in your eye or a face wound you will be glad you have it!

mines prob gets most of its use picking trout from teeth after dinner
Or just for making sure I don't look like a compleately Scallywag while trying to hitch it back to town for some grub and a pint !

Bottom line! While trekking,hunting or just chillin in backcountry. For the weight I wouldn't be caught dead without one!