BOLSA™ is made out of injection molded TR-90 to ensure light-weight and 100% skeletal memory retention for consistent fit and comfort. As with all of our styles, BOLSA is finished with 100% UV protection through our proprietary and optically superior SR-91® polarized lenses. Bolsa™ Also Features: A smaller size fit for those with narrow faces Impact resistant and lightweight SR-91 Lenses that reduce glare and provide razor sharp clarity A micro-fiber cleaning bag and a protective case Patented by Kaenon, SR 91® is a high performance, durable, lightweight, and impact resistant lens material. This unique material offers razor sharp clarity, and with the addition of glare 860®, its polarized form, SR-91® boasts superior glare reduction. It is trusted by the world's top athletes and is good for extreme sports.