Multicoated aspherical eyepiece lenses and BaK4 prisms: Deliver bright high-resolution images under all lighting conditions. - Generous eye relief: For a clear and comfortable view especially for eyeglass wearers. Includes turn-and-slide rubber eyecups. - Fully waterproof/fogproof: Nitrogen-filled and O-ring sealed. - Smooth central focus knob: Fast range of focus for quick viewing. - Durable and protective rubber-armored coating: Provides a sure non-slip grip wet or dry. - Focusing System: Central Focus - Magnification: 8 x - Objective Diameter: 25 mm - Angular Field of View (Real): 6.3 - Angular Field of View (Apparent): 47.5 - FOV at 1000 yds: 330 ft - Close Focus Distance: 9.2 ft - Exit Pupil: 3.1 mm - Relative Brightness: 9.6 - Eye Relief: 15.5 mm - Size (Length x Width): 3.9 x 4.5 in - Weight: 12.5 oz - Interpupilary Distance: 56 -72 mm - Prism: Porro