Extra-low dispersion (ED) glass produces outstanding color fidelity and high quality image dielectric high-reflective multilayer prism coating bak-4, phase coated roof prisms 100% fully multi-coated optics, green-coated on four sides of the prisms and large aperture apochromatic lens, higher image quality in all lighting conditions , even water-repellent coatings for the lenses armored rubber binocular 20.00 mm long eye relief and twist up eye-cups great for eyeglass wearers minimum focus distance of 4.92ft magnesium alloy body provides light weight fully waterproof and fog proof, nitrogen filled, submerge to 1 meter for 15 minute's wide field of view at 1000 yards: 309.20 ft. Ergonomic open hinge design specifications: Binoculars series knight ED-series binoculars focus system central lens ED (extra-low dispersion glass prism system dash (bak-4) coating FMC (fully-multi coated) resolution 5 size full size binoculars eye relief 20.00 mm waterproof yes fog-proof yes features waterproof & fog-proof magnification 10 x brand Snypex objective lens diameter 50 mm field of view at 1000 yards 309. 20ft. Field of view degree 5.9 exit pupil 4.88 mm focus type center focus close focusing distance 4.92 ft. Groups and elements for eyepiece 4g5e groups and elements for objective lenses 3g4e prism type open hinge /roof prism binoculars barrel mg-al weight 30.68 oz. Dimensions 6.10 x 5.31 x 2.32 inch.