Serengeti Velocity sunglasses feature a sporty,rounded rectangle shape with a double bridge Serengeti is the trusted brand for pilots and professional drivers, Serengetiensures safety of their eyes withexceptional clarity and performance. Full rim frame made from hypoallergenic titanium is strongand corrosion resistant Unisex design Displays Serengeti S logo on lens Spring hingesretainthe initial balance, noneed for frequent adjustments Adjustable nosepads for a custom fit Available in various color options Serengeti protective carrying case and cleaning cloth includedThese sunglasses are available with polarized lenses on certain colors. Polarized lenses have a filter within the lens that blocks the wavelengths of light that cause glare. They can greatly enhance contrast and allow for greater depth of vision, especially in water. They are ideal for any situation where glare reduction is necessary, like driving or playing sports.The sunglasses are available on certain colors with gradient tinted lenses - Gradient tints are tints that start off at a darker color at the top of a lens and then gradually lighten towards the bottom of the lenses. These tints are great for fashion and for reading outside on sunny days. Gradient coatings work by allowing an appropriate amount of light to filter through in certain areas and less in places where protection is most necessary.These sunglasses are available with photochromic lenses on certain colors, which are light sensitive and adjust to varying light conditions. The color goes from dark in sunny conditions to clear in cloudy or indoors conditions.