Serengeti Gio Sunglasses, Shiny Dark Demi Tortoise with Drivers Lens Base Curve: 8 Rx; Temple Length: 130mm/Spring Hinges; Lens Size: 60 x 39 x 64 mm The Sport Classic Frame give style and confidence. The Drivers brown-colored lens is ideal for driving, because it adjusts to the changing light conditions that are inevitably encountered on the road. 24% Transmittance lightened lens/9% transmittance darkend lens.