Why interchangeable? Because no one lens can provide optimum visual performance across the complete range of performance needs. Why Suncloud Sport for interchangeable? Because no other brand provides better comfort, ft, polarized mirrored lenses, and consumer value than Suncloud.GRILAMID NYLON FRAMES: Suncloud injection molded frames are crafted from optical grade Grilamid TR-90 for quality ft, ?exibility, and lasting durability in all environmental conditions MEGOL: Suncloud Sport frames incorporate hydrophilic megol features in the nose and temple tip areas to help your glasses stay put on your face during sports and performance activities. This specialized material increases retention when it gets wet from perspiration or atmospheric conditions. INTERCHANGEABLE LENSES: Designed for all day performance in varying conditions, Suncloud Sport frames include two sets of interchangeable lenses for varying light conditions. From early morning and dusk conditions with the high-contrast rose lens, to mid-afternoon bright sun with the polarized lenses; you can confdently count on your. Suncloud Sport eyewear to provide comfortable vision and optical performance all day.