Bak-4 glass prisms reflect more light to your eyes which will give you brighter and sharper image.
Multicoated optics effectively reduces reflected light and increases the transmission of light giving you a brighter image than normal single coated lenses
Twist up eyecups with intermediate stops allow you to set the eyecups to the ideal eye relief for you eyes
Long eye relief can be particularly important for eyeglass wearers because longer eye relief allows them to still see the entire field of view.
Waterproof to protect the binocular in the harshest weather conditions or if accidentally submerged underwater