Ray-Ban RB4147 sunglasses are fashionable and bold with larger rounded square lenses in propionate plastic frames which offer maximum sun protection while embracing a chic Hollywood look. Description Lens Size This is the 56mm lens size. Clarity & Comfort Crystal lenses with anti-reflective coating have been shaped by Diamond Tools and offer distortion free vision. UV Protection Every lens blocks 100% UVA, UVB & harmful Blue light (up to 400nm) Impact Resistance Lens A steel ball is dropped on the lens from a height of 1.27m. After the chemical hardening, the impact resistance of Ray-ban glass is more than doubled. Scratch Resistance Lens Submitted to 500g of a special abrasive sand oscillating for 600 cycles. Compared to the most commonly prescribed lenses (CR-39), they are 12 times more resistant, thus exceeding by far the international standards Weatherproof Lens The Ray-Ban lens is exposed to consecutive cycles of UV light and moisture. The result after 120 hours of intense testing: no visible change in the colour and no surface damages on the lens.