Featuring the Serengeti Drivers lens the most versatile lens, enhancing your vision in all conditions. Featuring Serengeti sunglasses patented Spectral Control System, the Drivers lens is engineered to improve contrast and reduce eye fatigue. Photochromic lenses automatically adjust according to the amount of UV exposure. Lens technology keeps colors true while eliminating annoying "blue blur". The Spectral Control System virtually eliminates eye fatigue and strain.