Filtrate Eyewear AUDIO Sunglasses- Matte Black with Grey Lenses 00 Stainless Steel, high quality, strengthened hinges. 100% UV Protection, with high quality polycarbonate for a more optically correct lens. Polycarbonate is light weight and provides high impact resistance. High quality polycarbonate memory flex injected frames. Filtrate uses only high quality materials in all our frames to survive the good times and the bad. 6 - 8 Base frame curvature of the lens and/ or frame of a sunglass