On WPSMB, Bob R wrote:
The reason a real signal mirror works so well is the "retro-reflective aiming aid" in the hole (so it's not really a hole). Looking through it, with the mirror held close to your eye, the location of the spot is vividly obvious even if it's too far away to actually see it hit. Move the image of this spot over to your target, and you're "spot on." No guessing as to where the reflected light is going, and--for the people in the helicopter--no guessing where it is coming from.
...(For example, Adventure Medical's mirror is $9, weighs 0.3 oz)Bob, I have never seen a mirror like that. I'm going to order one soon. It sounds like a much better option than anything I have seen.
So many times, I have seen a mirror with a hole for a string or whatever, but NO aiming aid. I think most people would be unable to aim one of those effectively.
REI link: mirrorAdventure Medical link
