JEFFERSON 51 RX Eyeglasses by SALT. Color: Black, Evergreen, Smoke Grey, Whiskey, Size: 51-20-148. Inspired by Nature’s effortless beauty, SALT. glasses are head-turning pieces-of-art, refined and elegant. Manufactured in Japan from the best-in-class materials to the highest standards, they are guaranteed to last for generations. Designed by opticians, the glasses are paired with the premium-grade SALT.’S proprietary lens that is the clearest lens in the industry. The retro-inspired shape goes with everything and will make any outfit—yes, even your workout clothing—instantly chic. Utilizing modern technologies and proven materials, this iconic SALT. frame offers the perfect blend of style, functionality, and optical performance.