Easily attach these Clip-On Magnifying Glasses to the brim of your hat and start tying flies. Clear acrylic lenses deliver a sharp, distortion-free view. They are available in 1.75X (equivalent to a +3 diopter), 2X (equivalent to a +4 diopter) or 2.25X (equivalent to a +5 diopter). Protective soft case included. Available: 5 Diopter,4 Diopter, 3 Diopter.