Nrc eyewear nrc x series x3 sunglassesthe nrc eyewear nrc x series x3 sunglasses are inspired by nrcs constant desire for innovation the x3 series have a photochromatic lens coating that adapts to the level of brightness automatically and is shaped to increase ventilation reduce fogging of the lens protect the eyes from solar radiation and to provide complete vision coverage perfect for competition and training ridesthe carl zeiss one piece lens has been designed using a base colour of gold