OPTX 20/20 Reading Lenses adhere to the inside of your glasses by static cling adhesion. They are removable and reusable so you transfer them from glass to glass. No glues or adhesive are necessary. OPTX 20/20 lenses easily install with water. OPTX 20/20 adds optically correct magnification to your shooting glasses, sunglasses, safety glasses, and prescription eyewear. The lenses turn your favorite glasses into bifocals simply with a drop of water. No more squinting. No more stacking reading glasses with sunglasses. OPTX 20/20 can be trimmed to fit any glasses. Turn you favorite pair of sunglasses into bifocal readers without the expense of custom prescription lenses. 1.25 Diopter.