Serengeti 8472 Mattia Polarized Drivers Sunglasses, Shiny Dark Tortoise Frame/Black A full 20% thinner and lighter, our ultra-light mineral glass lenses are made from only the finest materials, giving you the best visual Optics in the industry Expertly produced and cured from all-natural cotton, our cellulose propionate acetate is not only handcrafted to be lightweight, but can be made into beautiful patterns and brilliant hues With superior Serengeti Polarization, the fatigue, discomfort, squinting and impaired vision associated with all forms of glare simply go away. Polarization available in select models only. Darkening in bright sunlight and lightening in overcast conditions. Serengeti photochromic technology allows your eyes to adapt to any light Serengeti spectral control technology filters specific light wavelengths, sharpening the way you see color contract and improving visual definition