The PERCEPTION™ is a fully integrated vision correction sport sunglass. The easy-in, easy-out optical insert allows you to wear the product with or without contact lenses. In addition the insert can handle a wide range of prescription correction factors. The easy-action, flip-up lens technology enables you to instantly see clearly when light condition changes dramatically by flipping up the entire lens system. The scientific geometric design, adjustable nose and temples system and advanced lightweight material offer the ultimate custom fit fog free performance and contemporary styling. The interchangeable lenses allow you to manage any light condition. Optional elastic strap ensures a snug, comfortable fit.