BARSKA Blueline 20x,40x100 Waterproof Jumbo Binocular w/ Premium Hard Case Field of view (ft at 1000Yds/M at 1000M): 131/43.8 at 20x, 63.9/21.3 at 40x exit pupil (mm): 5at20x, 2.5at40x Eye relief: 23.6mm at 20x, 18.4mm at 40x Close Focus (ft./M): 65.6/20 Tripod adaptable ; Triplet Optical System Waterproof construction with a rigid all -metal body Dual power interchangeable 20x and 40x eyepieces of high power viewing Multi-coated optics coupled with the large 100mm objective lens maximizes light transmission, enhancing clarity Large semi-apochromatic 100mm objective lenses with high quality BAK-4 prisms Ideal for celestial and terrestrial observations, and packaged in a premium aluminum hard case for protection and storage