Protech Sunglasses offer great protection on the water and look great around town. The frames are made of lightweight but very durable PVC and the lenses are serilium - the purest polycarbonate known to man. The frames are designed with the motion fit system for a comfortable fit that hangs on securely. PVC Plastic frame material is light and very durable. It is precision molded to form the frame of the sunglasses. The frames are flexible and maintain their shape very well.