Glass Lenses,Nylon Made in US Costa's most high tech lens - 580 Glass provides superior clarity, scratch-proof, 100% UV protection and the best polarizing efficiency available. Blue Mirror Polarized is best for bright, full-sun situations on the open water and offshore. Costa's co-injected bio-based nylon frame material is both tough and durable, while offering a comfortable fit. 100% polarization kills reflected glare and reduces eye strain. Built by hand and backed for life.