Our original brand products. Oakley sunglasses SPLIT JACKET: Interchangeable lenses compatible with split jackets. Standard features include ultraviolet (UV) protection, hard coat, and water repellent coat. In addition, this is a high-spec lens with prism correction, which is not normally available in cheaper lenses. Photochromic lenses are lenses that have a photochromic material that develops color with the energy of ultraviolet rays and fades with the energy of visible light and heat. The density of photochromic lenses depends on the intensity of ultraviolet rays and temperature. Exposure to strong ultraviolet rays promotes color development, but higher temperatures inhibit color development. Even if the UV rays are strong, there is a tendency for the color to change only slightly in high temperatures such as summer. Photochromic lenses gradually deteriorate over time due to the effects of ultraviolet rays, etc., resulting in a decrease in density and changes in color tone. Please note that the dimming function is not permanent.