The DISTRICT's interchangeable lens system creates a sleek and subtle design allowing comfortable wear in the city or on the trails. Smith's Interchangeable lens system utilizes distortion-free, 9 base lenses to provide precise optical clarity and maximize coverage while minimizing peripheral exposure to sun, wind, and glare. With over a dozen replacement lens tints to choose from, the Smith Slider series provides versatility across the full spectrum of light conditions and sport eyewear enhancements.