Nrc eyewear nrc x series x5 sunglassesthe nrc eyewear nrc x series x5 sunglasses are inspired by nrcs constant desire for innovation the x5 series feature a lens that 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 and brown instead of the common grey base layer this increases the len