Nikon 16x50 Aculon A211 Binocular (Black) Bak-4 porro prism 
 
Optical Performance
Powerful 16x magnification allows for highly detailed observations of distant subjects
Large 50mm objective lenses improve light-gathering ability to ensure distant views remain bright and sharp for better resolution, even in challenging light conditions
Traditional Porro prism light path produces a rich depth of field, allowing the user to discern the relative distances between objects being viewed
High refractive index BAK4 prisms deliver a round exit pupil and a crisp and clear image with limited edge distortion
Aspherical eyepiece lenses correct spherical aberration to produce clear and crisp images, with reduced edge distortion and astigmatism
Anti-reflection multi-coated optics produce neutral and accurate color fidelity, and improve contrast and image brightness
Wide 61° apparent angle of view reduces the appearance of visible hand shake that is common when holding high-power optics such as this
220-foot field of view at 1000 yards
Use and Handling
Large slip-resistant center focus wheel is easy to manipulate, even while wearing gloves
Right-eye dioptric correction compensates for individual user's optical prescription for clearer and sharper views
56-72mm interpupillary adjustment range
Fold-down rubber eyecups for comfortable use with or without eyewear
Tripod mountable with adapter for hands-free use with reduced vibration and arm fatigue
12.6mm eye relief allows easy viewing without eye fatigue, especially during long observation sessions
3.1mm exit pupil
Construction Details
Environmentally friendly Eco-Glass is made without lead or arsenic
Protective rubber armoring provides a comfortable slip-resistant grip even in cold weather
Ergonomically sculpted grips
Tripod adapter included for hands-free use to eliminate the vibrations, shakes, and arm fatigue that are common when holding high-power/large-objective optics
One-piece tethered ocular rainguard protects eyecups
Objective lens caps can be clipped to neck strap to avoid losing them during observation sessions
Weight: 32.5 ounces