The Firefly combines a 2.5X flip-down magnifier with an LED to aid in tying on tiny flies or adding new tippet in even the worst light conditions. The Firefly clips to the brim of a hat for convenience and folds out of the way when not in use.
Poor quality with a line down the center of the lens. I put them on and immediately knew that I was going to return this to Cabelas. I am sure the magnification and light would work perfectly if you could keep from going crossed eyed!
These things work great! Put em on first thing in the dark, and they will take care of you until the sun comes up. The ONLY thing i didnt like about them, was I wish the lense folded up out of the way more, because in true dark light, the lite shines off the lense and blinds you. Dont expect to see distances with them, but GREAT for tying on a fly in the dark.