Vortex Diamondback HD 10x50 BinocularsThe Vortex Diamondback HD 10x50 Binoculars earn their HD stripes by upgrading their prisms with dielectric coatings to go with their phase correction coatings, and new lens coatings designed to match with the prisms. External lenses are coated with ArmorTek, a scratch resistant and oil repellent application. The optics deliver 315' at 1000 yards, 17mm eye relief, and a surprising 6' close focus, which is very rare in a 50mm binocular. The rubber