.75mm lead equivalency radiation-reducing SF-6 Schott glass lenses SF6HT leaded glass lenses for up to 20% more light transmission than any other brand Brazen Boost is a full rim frame for men and women, made of plastic. It has a rectangular shape with a single bridge Lightweight Wrap-Around Frame Trendy Matte Dark Obsidian Color Brazen Boost Plano Leaded Eyewear in Matte Dark Obsidian. Brazen Boost is a full rim frame for men and women, made of plastic. It has a rectangular shape with a single bridge. The frame features a rubber temple to provide a secure grip. This product offers our standard high quality, distortion-free S.75mm lead equivalency.