The Costa Del Mar Men's Saltbreak Polarized Sunglasses are bold, hardworking frames that are just eye-catching. Made of a durable nylon and with sturdy integral hinges, they're as tough as they look.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.