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The Switch Cortina Interchangeable Lens Sunglasses have a unique magnetic lens swapping system that is, by far, the easiest lens swap system you'll ever see. Lenses switch quickly, with no awkward tabs or clips to operate. Just put the lens near the frame and it jumps into place. The frame is made of light, but durable nylon with sticky rubber to hold on to your head. The lenses are polycarbonate to eliminate 100% UV and provide impact protection.Extremely easy-to-use lens interchange system.Durable but light nylon frame.Polycarbonate lenses provide 100% UV (ABC) protection.