Serengeti Nunzio Sunglasses, Shiny Carbon Fiber/Polar PhD 555nm Lens Medium/Large fit, Universal Ideal for bright light conditions, the 555nm glass lens manages yellow and green light transmissions to cool and relax the eyes Our photochromic technology works by embedding molecules within the lens to constantly adjust to changing light conditions By managing colors within the visible light spectrum, Spectral Control technology gives you stunning, high-definition contrast and color enhancement Serengeti's polarization technology is specifically engineered to eliminate distracting glare, giving the wearer unsurpassed clarity and comfort