The Carson VM-12 is a set of clip-on, flip-up magnifying glasses that attach to the brim of most caps and hats. Perfect for fly-tying and all fly-fishing needs. Complete with protective soft-pouch, its crystal clear acrylic Lenses give you a sharp, distortion-free view that allows you to see even the finest details with ease. These Magnifying glasses are 2x power equivalent to +4.00 diopter. Keep these clip-on Magnifier lenses in your tackle box so you always have them at the ready.