HIGH QUALITY AL-MG FRAME - Al-Mg frame is relatively light in weight compared with ordinary metal frame. And It is tough, corrosion resistant, extrusion resistant, high wear resistance, safety and environmental protection. These sports sunglasses are perfect for both men and women.Carbon fiber is chemically stable, resistant to acid, alkali and salt. It is superior to other materials in anti-corrosion and can be kept intact in damp and harsh environment.