Costa's most high tech lens - 580 Glass provides superior clarity, scratch-proof, 100% UV protection and the best polarizing efficiency available. Silver Copper Mirror Polarized is well-suited for environments with varying light such as stream fishing. 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.