Glass Lenses. Made in US. Costa's 580 Polycarbonate provides high clarity, impact- and scratch-resistance along with lightweight all day wear-ability. 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.