The VM-12, VisorMag +4.00 Diopters (2x Power) Clip-On Magnifying Lens for Hats or Caps 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 +4.00 diopters equivalent to 2x magnifying power. Keep these clip-on magnifier lenses in your tackle box so you "always have them at the ready."