Serengeti 8194 Pavia, Shiny Dark Tortoise Frame, Polarized Drivers Lens 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 Designed for comfort that feels truly customized, wire flex technology bends to the contours of the face. It features a flexible and strong blend of nickel, Silver and stainless steel 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