Ray-Ban Sunglasses 4179 601/71 Black Green is from the latest Liteforce series from Ray-Ban which used a thermoplastic material used in aerospace which gives superb durability and comfort in a plastic frame but above all lightness. The curved top bar is the thickness of a metal frame which is of course very thin but still strong enough to support the polycarbonate lenses in a plastic frame. The sleek rectangular shape is ultra-modern to match the high-tech materials to make you feel like you are wearing the future.