Serengeti RX Eyewear Small Aviator Sunglasses (Gunmetal/Black Tannery, Polarized) polarized Photochromic technology designed to constantly adjust to changing light conditions Spectral Control technology gives you stunning, high-definition contrast and color enhancement Polarization technology engineered to eliminate distracting glare All Serengeti lenses offer the latest in photochromic technology, which constantly lightens and darkens throughout the day to ensure you see every detail. Light silver coating further reduces eye strain by acting as a protective shield against glare.