In addition to a wide range of patented shapes/sizes and Flex2Fit? temples, Cocoons have many features that cannot be found on any other fits over sunglasses. The side lenses are optically correct polycarbonate; this means that they will never shrink or fall out, a common problem with generic fit over sunglasses. The Soft Touch? nylon frame is extremely resilient and can withstand the harshest of treatment without breaking. The durability of the frame can be demonstrated by twisting and bending it. The durability of Cocoons is reiterated by the Live Eyewear limited lifetime warranty. Coccons also feature gray, amber or yellow Polar?? lenses.