Ruggedness, waterproof, lightweight construction, and unsurpassed quality are key to the Golden Ring spotting scopes. Xtended Twilight Lens System for twilight. DiamondCoat 2 on exterior lens for higher light transmission and abrasion resistance. Better optical clarity from lead-free glass lenses, produced with none of the environmentally damaging by-products. Also, non-lead based lenses are lighter in weight. Extreme vivid color, and life-like clarity thanks to calcium-fluoride lenses.