The Costa Del Mar Men's Brine Polarized Sunglasses are true high-performance equipment, using integral hinges, Hydrolite™ temples and co-injected, co-molding technology to deliver comfort and fit that lets you focus on dragging fish into the boat. The frame is made of heavy duty TR 90 nylon frames and has an internal hinge. The lenses are polarized with Costa's 580 technology that kills reflected glare and reduces eye strain. The Blue Mirror lens is for harsh sun and has a natural contrast. The Green Mirror lens is for bright sun and has a high contrast.