Costa Del Mar Sea Fan Topaz Fade Sunglasses Grey Lens 580P Comfortable medium fit, Optical spring hinge, Heavy-duty TR 90 nylon frame. Includes hard case, 100% UV light blockage for max protection. 100% polarization kills reflected glare and reduces eye strain, Built by hand and backed for life. Every pair of Costas include a lifetime warranty. 100% polarization kills reflected glare and reduces eye strain, Built by hand and backed for life. Every pair of Costas include a lifetime warranty. Glass lenses have the greatest clarity and are scratch resistant.