The lens are made of plastic or crystal and come in lots of colors. Their non-polarized lens blocks out almost 99% of all ultra-violet rays. Their polarized lens reduces squRayban Sunglassesinting and eye fatigue as it blocks out the glare from all reflective surfaces such as metal, snow, glass, and water as well as 100% of UV rays. Ray Ban recommends that customers take care of their sunglasses and protect them against damage. The sunglasses should be kept in a case when not in use and should be cleaned with the recommended soft cloth. The glasses are guaranteed against breakage due to defects material or workmanshipRayban Sunglasses. With care the glasses can last decades.