2531 Glasses by Lindberg. Color: 10, 20, 25, 30, 35, 60, 70, 75, 77, 80, 85, 90, 95, GT, U12, U13, U16, U9, Size: 53, 55, 57, Bridge: 22, Temple Length: 145, Temple Design: Basic. The frame 2531 by LINDBERG is all about square logic with a twist—it tapers slightly at the temple for a refined finish. High-grade titanium ensures comfort through long hours. It’s quietly distinctive and endlessly versatile. A wardrobe staple with high design DNA.