The The One Nero is a photocromic polarized lens made to adapt itself to the typical light conditions that are to be found in the mountains. The colors of the pigments change, and the filter category varies between S2 and S3, from yellow to black depending on the lighting conditions. In bad wheather conditions the yellow pigmentation with the polarized filter increments the perception of the contrasts and the shape of the run, while in strong light conditions the lens gets darker erasing the reflections on the ground. You are not sure about what the wheather will be like today? Choose The One and you' ll always have with you the best lens.