SyntheticMade in USCosta’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. Every pair of Costa Sunglasses includes a limited lifetime warranty.