NEW AND IMPROVED! EnChroma® Derby Cx3 Sun SP (for Strong Protans) is an iconic browline frame with Cx3 Sun SP lens technology engineered to deliver clear, bright colour and 100% UV protection for those with strong protan colour blindness. Features a combination of cellulose acetate and stainless steel materials with adjustable nose pads. The sophisticated silhouette offers trend-forward stylings for all face shapes. Durability qualities inherent in the premium acetate and stainless steel spring hinges provide a more flexible fit that contours to the face over time.