This magical photochromic lens are based on the intensity of sunlight and ultraviolet light, darkening the light grey lens. What’s more, these glasses protect the eyes without interfering with your perception of color. Plus its fashion Square design, always match your daily dressing demand(may not change obviously under weak UV lights) Photochromic lenses shift from reading glasses indoor to reading sunglasses outdoor, also you can use it as normal photochromic sunglasses,Radiation protection, UV protection Lightweight frame with photochromic lenses easy reading indoor and outdoor. Comfortable, lightweight body that won't hurt your nose,and protected thanks to the free cleaning cloth and case always clean within 30 days, please contact our customer services without hesitation. We will provide the best solutions until the customer is satisfied. You have no risk to try! Bifocal reading glasses: accommodate for both near and far vision by adding a unique lower lens with add vision value for reading and near vision. Transition photochromic gray bifocal reading glasses lens optical glass containing silver halide microcrystals, Phototropy reversible reaction according to the principle, In the sunlight and UV irradiation variable dark, Completely absorb ultraviolet and visible light absorption of neutral，Back to the dark, Can restore the colorless transparent.