Geared for speed. The Shift MAG gives cyclists and runners every performance advantage possible, from the superlight frame down to the nose piece. The coolest feature is no doubt the interchangeable lens technology. Snap the magnet on the side for quick, fingerprint-free lens changes. These Smith sunglasses come with one clear lens as well a color-enhancing ChromaPop lens. Flatter than most performance eyewear, the 5-base frames stay put with a two-position nose piece and no-slip temples. They give you a secure feel when you're going your fastest.