Base Curve: 6. Grilamid: Grilamid is a resilient type of nylon specifically formulated for flexibility, stability, and durability. Polycarbonate: Polycarbonate is lightweight, comfortable, impact resistant, and provides UV protection. Happy Lens: SPY's color and contrast enhancing happy lens allow in the sun's "good" rays that studies suggest create an uplift in mood and alertness, while still blocking the sun's "bad" rays.