Ray-Ban ® Liteforce Tech RB4179 sunglasses are a perfect combination of iconic design and innovation. A new bio-material made of a semi-crystalline thermoplastic used in aerospace, automotive, and for medical implant technology gives you superior lightness, durability, and comfort in a plastic frame. These rectangular sunglasses for men feature a curvacious top bar in a super light injected construction, allowing the same thickness of a metal frame.